Image: Dorit Thies
In Brief
- Humans are the only primate species that has mostly naked skin.
- Loss of fur was an adaptation to changing environmental conditions that forced our ancestors to travel longer distances for food and water.
- Analyses of fossils and genes hint at when this transformation occurred.
- The evolution of hairlessness helped to set the stage for the emergence of large brains and symbolic thought.
Among primates, humans are unique in having nearly naked skin. Every other member of our extended family has a dense covering of fur—from the short, black pelage of the howler monkey to the flowing copper coat of the orangutan—as do most other mammals. Yes, we humans have hair on our heads and elsewhere, but compared with our relatives, even the hairiest person is basically bare.
How did we come to be so denuded? Scholars have pondered this question for centuries. Finding answers has been difficult, however: most of the hallmark transitions in human evolution—such as the emergence of upright walking—are recorded directly in the fossils of our predecessors, but none of the known remains preserves impressions of human skin. In recent years, though, researchers have realized that the fossil record does contain indirect hints about our transformation from hirsute to hairless. Thanks to these clues and insights gleaned over the past decade from genomics and physiology, I and others have pieced together a compelling account of why and when humans shed their fur. In addition to explaining a very peculiar quirk of our appearance, the scenario suggests that naked skin itself played a crucial role in the evolution of other characteristic human traits, including our large brain and dependence on language.
This article was originally published with the title The Naked Truth.
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109 Comments
Add CommentDesmond Morris answered this question years ago. We have naked skin for the same reason we have tear ducts; our species spent ten million years living in and off the ocean before moving back to the land.
Reply | Report Abuse | Link to thisjameylynne, spoiling revenue and subscriptions :P
Reply | Report Abuse | Link to thisJudging by the hair on my legs, I must be one of the long lost ancestor.
Reply | Report Abuse | Link to thisElaine Morgan's "The Scars of Evolution" expanded on Desmond Morris and is an excellent piece of work.
Reply | Report Abuse | Link to thisIt seems obvious that when early humans began persistence hunting in Africa it started an evolutionary pressure to improve endurance. Those who could shed heat better had more endurance and thus more successful in the hunt. More food more offspring. The resulting adaptations produced tall, slim, hairless physiques that sweat. Evaporation of sweat off exposed hairless skin cools the body more efficiently than hairy skin. Persistence hunting is the reason humans are tall, hairless, sweaters that can run marathons.
Reply | Report Abuse | Link to this"our species spent ten million years living in and off the ocean before moving back to the land." Oh the humor
Reply | Report Abuse | Link to thisI have not read the article by I have contended for a long time that the use of fire and hairlessness are closely interlinked. How could a hairy ape safely control or utilize fire? If fire was a key to survival (i.e., as protection against predators, a way to make foods safer to eat, and to withstand adverse environmental factors) then there must have been adaptations to humans to enable use to use it effectively. Less hairy members of a group were less likely to catch fire, and more likely to survive fire, enabling them to pass on their genes more frequently. Also, the members of a group may have associated hairiness with flaming family members, and selectively chose hairlessness as a more desireable feature of those able to control fire. Perhaps the ability to control fire was seen as a symbol of power, controlled by the less hairy.
Reply | Report Abuse | Link to thisI have not read the article by I have contended for a long time that the use of fire and hairlessness are closely interlinked. How could a hairy ape safely control or utilize fire? If fire was a key to survival (i.e., as protection against predators, a way to make foods safer to eat, and to withstand adverse environmental factors) then there must have been adaptations to humans to enable use to use it effectively. Less hairy members of a group were less likely to catch fire, and more likely to survive fire, enabling them to pass on their genes more frequently. Also, the members of a group may have associated hairiness with flaming family members, and selectively chose hairlessness as a more desireable feature of those able to control fire. Perhaps the ability to control fire was seen as a symbol of power, controlled by the less hairy.
Reply | Report Abuse | Link to thistaerog:
Reply | Report Abuse | Link to thisBefore you deride another persons post please do some research.
Read this:
http://web.ukonline.co.uk/michael.magee/awwls/00/wls137.html
or listen to Ted talks - Elaine Morgan. Remember just like whales and other aquatic mammals you also store fat under your skin.
"Less hairy members of a group were less likely to catch fire, and more likely to survive fire..." If that's the case then why do I have hair in the last places on my body that I'd like to have burned?
Reply | Report Abuse | Link to this"our species spent ten million years living in and off the ocean before moving back to the land" First off, our species has only been around a couple hundred thousand years and second I don't believe that there is sufficient evidence to suggest that the Homo genus was semi-aquatic. Unfortunate, because having webbed-fingers and toes would have been great when I was a swimmer.
Perhaps you mean subsistence hunters?
Reply | Report Abuse | Link to thisI have not read the article by I have contended for a long time that the use of fire and hairlessness are closely interlinked. How could a hairy ape safely control or utilize fire? If fire was a key to survival (i.e., as protection against predators, a way to make foods safer to eat, and to withstand adverse environmental factors) then there must have been adaptations to humans to enable use to use it effectively. Less hairy members of a group were less likely to catch fire, and more likely to survive fire, enabling them to pass on their genes more frequently. Also, the members of a group may have associated hairiness with flaming family members, and selectively chose hairlessness as a more desireable feature of those able to control fire. Perhaps the ability to control fire was seen as a symbol of power, controlled by the less hairy.
Reply | Report Abuse | Link to thisHairlessness also makes it easier to find and remote ectoparasides. And if I recall right human skin is more enervated that that of other mammals, making it easier to sense little critters crawling around on us. It also makes us more sensual--both literally and figuratively--which would enhance the human mating/bonding processes required to support females and offspring during our lengthy childhood dependency.
Reply | Report Abuse | Link to thisGuess this rules out Chewbacca, huh?
I have read the article, and I thought it did a very good job debunking Morgan.
Reply | Report Abuse | Link to thisIf you had bothered to read the article, you would know it does a pretty good job at refuting the aquatic ape theory.
Reply | Report Abuse | Link to thisI apologize for stuttering - I'm new here. If it's possible to delete my additional posts, I'd appreciate it.
Reply | Report Abuse | Link to thisHey... I thought someone ate an apple and all the hair fell off at that point?
Reply | Report Abuse | Link to thisFrom an evolutionary biology view point it is clear that chicks without mustaches are better looking and men with less back hair are also better looking. Thus, one would expect them to have a evolutionary advantage. ;)
Reply | Report Abuse | Link to thisI agree that right now it seems most likely that we shed the hair for endurance. The aquatic human idea is fun and has some merit since we prolly figured out early that coastal living has its advantages, but full-on, all-day like dolphins is stretching it because if that's the case we would've quickly adapted a better neck and head for swimming and ours are 100% land animal.
Reply | Report Abuse | Link to thisHumans have the thickest subcutaneous fat of any primate. So humans are naked because they use their thick subcutaneous fat for insulation rather than hair. And this was originally an aquatic adaptation.
Reply | Report Abuse | Link to thisHumans developed subcutaneous fat because they're ancestors were once specialized in wading into shallow marine waters to feed on benthic marine invertebrates. This is evident by that fact that humans are the only catarrrhine primate with multipyramidal kidneys-- an adaptation that is nearly universal in marine mammals that serves to expedite the excretion of hypertonic levels of salt through the urine.
Marcel F. Williams
Are we the only primemates that sweats (sweat glans) I had always heard it was man and horses that sweat?
Reply | Report Abuse | Link to thisWhat he said
Reply | Report Abuse | Link to thisHumans were hairless long before they mastered the use of fire. It has to be another reason then fire. Regarding the ocean, all of the primates have their origin in the ocean if we go far enough. Why only the human primate is naked is still not answered satisfactorily at all.
Reply | Report Abuse | Link to thisas a response to your first question, do you have a lot of hair in any place that would be near or handle fire?
Reply | Report Abuse | Link to thisHorses use apocrine glands for sweating. Humans use eccrine glands for sweating. All catarrhine primates have eccrine sweat glands distributed over the bodies but only humans and the patas monkey have functioning eccrine sweat glands. After humans, the great apes have the most eccrine sweat glands but they have all been deactivated. And a huge proportion of human sweat glands have also currently non-functional.
Reply | Report Abuse | Link to thisMarcel F. Williams
Who's to say we didn't evolve from hairless dinosaurs and that we actually predate primates? Perhaps we evolved hair as an adaptation to the subconscious abstraction of conscious self-awareness. Also, hair can also evolve out of practical purposes, 1. heat dissipation; 2. protection from the cold. The article makes the assumption that we devolved hair. Maybe we acquired it. I think that it is probable that perceptive input influences evolutionary directions.
Reply | Report Abuse | Link to thisAnyone interested in a copy of my 2006 paper on the evolution of the human kidneys and marine mammals with multipyramidal kidneys can email me at: newpapyrus@yahoo.com
Reply | Report Abuse | Link to thisMarcel F. Williams
"Humans have the thickest subcutaneous fat of any primate. So humans are naked because they use their thick subcutaneous fat for insulation rather than hair. And this was originally an aquatic adaptation"
Reply | Report Abuse | Link to thisOne heck of a jump and quite allot of evidence that does not support it at all.
"to expedite the excretion of hypertonic levels of salt through the urine. "
Too bad it does not work . . . and have no evidence it did.
Take a good look here for a good dissecting.
http://www.aquaticape.org/
"When you examine how many distinct times aquaticism and semiaquaticism arose in mammals which are around today, you find that it's 31 times, and that of that 31 times, only 3 times did it lead to hairless mammals. The vast majority of times it led to still-hairy mammals."
Reply | Report Abuse | Link to thisIt has been suggested from some recent evidence that our ancestors' use of fire is far older than first thought. There is no way of definitely knowing when they used fire, nor is it possible to tell exactly when we lost our hair. We assume that the change was gradual because we don't have it now, and our ancestors probably had it at some point and we think that changes take a long time to occur without some driving force.
Reply | Report Abuse | Link to thisWe have incomplete fossil records, and very fascinating imaginations (at least some of us do).
I find the aquatic ape theory to be very romantic. There are some compelling ideas, but like most of what we "believe", it is based on assumptions with very little evidence.
UFO believers will say that we were a hairy ape that was crossbred with an aquatic animal by aliens a hundred thousand years ago. No proof, yet no way to disprove.
We may never get answers, but lets be open-minded to alternative ideas.
mhaahahahaha
Reply | Report Abuse | Link to thismahhawwahhahahah
Reply | Report Abuse | Link to thisThe medullary pyramids of marine mammals do not work! How did you reach that conclusion?
Reply | Report Abuse | Link to thisMarcel F. Williams
"our species spent ten million years living in and off the ocean before moving back to the land" (Robert Schmidt)
Reply | Report Abuse | Link to thisAnd the ancestors of apes did not?
I have contended for a long time that the use of fire and hairlessness are closely interlinked. How could a hairy ape safely control or utilize fire? If fire was a key to survival (i.e., as protection against predators, a way to make foods safer to eat, and to withstand adverse environmental factors) then there must have been adaptations to humans to enable use to use it effectively. Less hairy members of a group were less likely to catch fire, and more likely to survive fire, enabling them to pass on their genes more frequently. Also, the members of a group may have associated hairiness with flaming family members, and selectively chose hairlessness as a more desireable feature of those able to control fire. Perhaps the ability to control fire was seen as a symbol of power, controlled by the less hairy
Reply | Report Abuse | Link to thisFanciful, far-fetched and unsubstantiated.
@baudrunner, "Who's to say we didn't evolve from hairless dinosaurs", well I guess anyone who has even taken a cursory look at vertebrate evolution. We didn't evolve from dinosaurs. We evolved from Synapsids. Dinosaurs evolved from Sauropsids. Our common ancestor, a basal Amniote, likely lived between 320 and 340 mya.
Reply | Report Abuse | Link to thisbrerlou, I think it was jameylynne who claimed that our species spent ten million years living in and off the ocean (very first comment), not Robert Schmidt.
Reply | Report Abuse | Link to thisNonetheless, I’m glad you pointed this out. The human lineage split from the chimp lineage somewhere around six million years ago, so anything that spanned ten million years must have included the ancestors of one or more of our ape cousins.
An alternative to Jablonski's theory is summarised as:
Reply | Report Abuse | Link to thisLoss of hair in hominid and human evolution is hypothesised to have occurred in two steps. The first step of partial hair loss is suggested to have occurred 1.5 million years ago and to have been the result of an increase in butchering, combined with a hygiene related mechanism similar to that behind the naked necks of vultures. The second step to todays near hairlessness is suggested to have involved a sequence related to Ambroses (1998) Toba hypothesis of human origins. In this sequence a population, trapped in a cold region by a sudden fall in world temperature (perhaps the Toba volcanic event), is forced to use clothing for survival. This then led, in line with the hypothesis of Bodmer & Pagel (2003), to strong selection against hair due to hygiene/parasite factors and to the gender dimorphism in hair that we see today. Subsequently, in this scenario, the use of clothing gave our ancestors a crucial additional advantage in competing with the Neanderthals. Finally, sexual selection locked in this near hairlessness even when, as with populations in the tropics, it and clothing were and are not needed.
Question: What about the savannah heat loss hypothesis, as argued by for example Jablonski (eg see her book Skin (2006)) ?
Answer: This hypothesis does not seem able to answer the questions of:
*Why, given the abundant evidence for evolutionary convergence (see Life's Solution by Simon Conway Morris), did lions and hyenas not evolve hair loss or why did human ancestors not evolve the panting mechanism?
Question: What about Jablonskis argument (Skin, p. 42) against the parasite/hygiene hypothesis that the archaeological record does not show evidence of awls and needles until 40,000 years ago.
Answer: Simple pointed sticks to make holes with the skins bound together by, say, string from twisted gut would seem to be initially adequate.
Question : What about Jablonski's argument (Skin, pp. 47-49) that the cooling demands of an enlarging brain was a primary driving force for loss of fur?
Answer: The cooling requirements for lions are almost certainly greater than even today's humans weighing a half to a third of their weight and have clearly not led to hairlessness.
Extracts from draft paper, Tony J Carey
Since the earliest African hominin, Sahelanthropus, is dated at between 6.8 to 7.2 million years ago, humans and chimps could not have split 6 million years ago.
Reply | Report Abuse | Link to thisMarcel F. Williams
God did it to us--so we'd invent coats.
Reply | Report Abuse | Link to thisIndoor living. Central heating. Snow blowers. And see-thru blouses.
Not to mention the ever popular *WAXING* Yea!
Truly that persistent hunting and endurance running (Trudat's comment) were important milestones in human evolution, but I don't see our "tall, slim, hairless physique that sweat" is the best adaptation to it, nor is a good one.
Reply | Report Abuse | Link to thisTake the other two biped endurance-runners -- Ostriches and Kangaroos. They have to run long distances everyday, but they're neither hairless nor straight. Instead they evolved long but bent legs, horizontal big trunk, relatively small head, etc. A good body plan for endurance running should be like this, not ours.
This seems to be the most thoughtful response I've seen so far, TonyJCarey. This issue of hair caught my attention as a child, (I'm still struggling with the notion of time) and I thought then, and still do that hair and a thicker epidermis portion of the skin only survive in animals that have them because they serve a useful purpose, otherwise they would have been largely de-selected out of the specie, surviving only as a rudimentary reminder of bygone times.
Reply | Report Abuse | Link to thisSo, once the idea of wearing the skins of other animals caught on, then both hair and hide gradually became a less viable factor in human evolution over time. To support this theory is the observation that people whose ancestors come from more tropical climates appear to have a thinner epidermis and considerably less body hair, generally, than descendants of people from temperate climes. (The, apparent, superiority of people of pure African descent in distance races, and of people of Caucasian descent in water sports might owe something to this sort of selection in terms of muscle to fat proportions, but that's just hypothetical I believe, and subject to cultural factors.)
Marcel, there is no agreement on where Sahelanthropus fits among hominidae. It could be a common ancestor to humans and chimps, it could be ancestor to neither or it could be solely on one side of the split. Its place hasn’t been determined. If someone can establish it as a human ancestor and not a chimp ancestor, then fine. Until then, the best estimate for the human-chimp split remains. Call it 6 million or call it 5 to 7 million. Either way, the original claim made by jameylynne remains nonsensical.
Reply | Report Abuse | Link to thisHmm, does not anyone believe in God, the creator of all things : omniscient, all powerful, all intelligent, knowing every truth of the universes and all the planets in all the galaxies that have multi billions of animals that we have never even seen or dreamed of as well as qua - trillions of
Reply | Report Abuse | Link to thispeople who look like us. He created everything in the spirit first. He is the greatest re-cycler of all things. In creating this planet (as well as others) he could easily have taken the components of a planet that had already been used to make this earth. There are millions of planets with millions of people. One day this will all be backed up visually and scientifically. In order for this earth to be fertilized he needed to put dinasaurs etc. on it first. Everything is eternal and everything is matter and capable of being changed and/or recycled. Do we honestly think we have the brains to create all this advancement in knowledge and technology without the inspiration of a higher, all knowledgable power?
What is now here, is comparatble to what a 1 year old child would know. Within 30 to 50 years our knowledge will increase 1000 fold if not 10 times that, and we will know the anwers to all these theories and questions that people speculate about. We are nothing without God, even many scientists and philosophers believe that now, But everyone has the great opportunity to believe what they want until further truth comes upon the face of the earth. Freedom to our own belief system and choice are great gifts.
Everything is it's own species. Man was made without hair, on purpose, it was not an earthly evolvement. Adam was not a dumb man, he was probably one of the highest intelligences ever born. But I believe in my Heavenly Father, as is my right. Believe what you want.
Sure "everything MUST have a purpose" because WE humans want it to be so. There for there must be GOD(s) to fit our want. Because we are all important . . UG!
Reply | Report Abuse | Link to thisPersonally, I could care less about what people "believe" since reality cares nothing about what humans believe. Some people want to figure out more of the reality we live in . . whether people believe in a GOD or 10 GODs or a magical turnip, reality "does not care" . . this is quite evident as religions and beliefs come and go through out history all saying that they are the thing to believe in . . till reality, time and other humans kicks them aside that is.
So we are interested in why people lost there hair as it is evident in the evidence so far that we did . . belief is irrelevant and unwanted in this task as the truth of the mater is what is looked for.
It seems like people have a few ideas but these have to be proved or disproved till the answer is found. This is a good thing.
I was an "aquatic ape" skeptic; now I'm more of an undecided agnostic. But please don't judge it by inaccurate information in comments - read the literature on the subject and decide for yourself.
Reply | Report Abuse | Link to thisThe time period is 2-6 million years ago, not 10m. The hypothesis seeks to integrate the following human anomalies:
- bipedalism. Bad for backs upright, great for swimming.
- vestigial webbing, sometimes to an exaggerated degree
- increased, insulating subcutaneous fat
- near-hairlessness
- kidney adaptations similar to other marine mammals
- a hooded nose and philtrum to help reduce water entry
- diving reflex
- voluntary breath control
- the vernix caseosa (the waxy coat on babies when born), found in no other land mammals, but present in some marine mammals.
I believe the location is centered on an inland sea, but I don't recall enough of the details. Still, even if you disagree strongly, reading the books is a learning exercise in understanding how the same data can have multiple radically different, yet logically sound interpretations.
Re: endurance. I wonder that we don't see more hairlessness in African predators, if this is such a helpful adaptation. But then, I can't afford a subscription, so I can't read the article. They probably explain it quite clearly :-)
The problem is most all of the points listed are not anomalies, most do not need a aquatic background to arise..
Reply | Report Abuse | Link to thissome counter arguments . .
Our skin is not adapted for constant water exposure like other aquatic animals (it gets water logged) the structure is also quite different. Most aquaticism and semiaquaticism arose in mammals ~31 times and only ~3 times did it result in hairlessness, and always in LARGE mammals. there are no hairless aquatic and semiaquatic mammal except for those which are fully aquatic and have been for tens of millions of years, or are either very large and almost certainly hairless due to the physics of thermoregulation, or they are both very large and fully aquatic for tens of millions of years.
-increased, insulating subcutaneous fat? less hair. smaller size.
-bipedalism? that is a strange one and the logic there really does not follow at all.
-kidney adaptations - are still not enough to help in salt water and no use in fresh.
-A hooded nose and philtrum? rather speculative and there is quite a list of alternatives.
-diving reflex? joking right?
- voluntary breath control? another one that needs more detail since mammals do have voluntary breath control??
- vernix caseosa? Babies shortly after birth loose that and do not develop oil glands till puberty . . so this is bad for them.
and so on . . .
If you look at these with the pre-belief if the result and over look various elements and facts . . it can make sense . . but you HAVE to accept the blinders for it to make sense. The harder you look at the pros AND cons of the "aquatic ape" concept it becomes very obvious that the pros are only pros if you squint :).
The idea of an "aquatic ape" doesn't require that we be actual amphibians or even a near approximation. It only requires that entering the water to retrieve food be advantageous AND that having less hair boosts that advantage in some way.
Reply | Report Abuse | Link to thisIf you have to cross ice cold water, and the weather is itself very cold (i.e. freezing to death is a real danger), it is recommended to remove your clothing and cross the water while keeping your clothing dry...because bare skin does not hold water and dries quickly. This allows you to warm up more quickly and thus avoid death to hypothermia (directly or otherwise...more subject to predation if you helplessly shivering in a blanket)
Suppose an ice age starts...the ancestors of humans could adapt by wearing animal skins...fine. Clothing removes some/most of the survival advantages of being hairy. As the ice age drags on, food becomes harder and harder to find on land. Our hominid ancestors are forced into the water to find food. Those w/o hair can dry off quickly and warm back up after exiting the water. Those that are hairier take longer to dry off or warm up and are more subject to death via hypothermia.
The hairier apes do not even have to have been dying from hypothermia that much more often, if at all. They could just be slower / inferior fisherman...or take longer to dry+warm up and then go back into the water for more food. Thus they have less prestige, less food, and less children and thus overall lower chance of reproducing.
In humans (or pre-humans), a survival trait does not necessarily have to be "needed" for a long period of time to become a dominant trait. Animals do not necessarily "notice" consciously that a survival trait is advantageous so their evolution is due purely to natural selection. The superior intelligence of humans/pre-humans could allow them to amplify the effect of natural selection. Perhaps call it "Amplified Selection" or Augmented Selection. The tribe members notice that the less hairy members or hairless mutant are superior cold-water fishermen/women. This information is conveyed to other tribes and perhaps within a generation or two, the entire race of pre-humans knows that being less hairy is better for fishing. More prestige becomes attached to being less hairy and even if the world warms up, it is too late for the "hairy" trait to survive because being hairy makes you less attractive (hell...it still does! :) ).
Dear Ms. Jablonski,
Reply | Report Abuse | Link to thisI’ve just read your article in Scientific American – “The Naked Truth”. You are probably wrong.
It is unlikely we became hairless because of the heat – no other terrestrial mammal has done that; none of the animals living on the savannah. As you say, it is apparently paradoxical that hair on our heads cools us (p 48) – exactly! It isn’t a paradox at all. That’s why all the animals that live full-time on the savannah have hair! The hairless ones, though big (elephant and rhino), also both have semi-aquatic ancestors (ask any paleontologist) or are currently semi-aquatic (the hippopotamus). And yes, over-heating is a problem but they use water to cool down – elephants hang out in watering holes as do rhinos, and hippos spend the day in the water. To say they are hairless without mentioning water is specious. It is also likely the main reason we’re hairless.
Also, only a minority of semi-aquatic mammals (seals) are haired – most are hairless. The hairy ones tend to live in cold climates where it is cold out of the water.
You re-iterate the theory that climate change forced our ancestors onto the savannah – this is an old hypothesis but has no supporting evidence and is counter to the behaviour of all other animals. Such conditions were (and are) more likely to force hominids to stream and lake banks where all animals go today when it is dry. Running away from water is not a good survival strategy or, therefore, an evolutionary advantageous action as is proposed by the savannah theory. The savannah theory is an old but ground-less hypothesis created when scientists had very little knowledge of synecology.
And not all carnivores roam about for their food. Lions, for example, mostly steal it from other predators, and all the big cats just wait for a herd of bovidae to wander by – very limited chasing is required on the savannah – ask a cheetah. Early hominids could have easily lived off food in the water, a more nutritious, easier to catch, easier to prepare food source.
Fact is, increased roaming by our ancestors is pure speculation and counter to the behaviour of other predators.
The aquatic ape theory is goofy but a better explanation exists that incorporates the idea of an aquatic background without the weaknesses of AAT: the multi-habitat amphibious theory. That is, our ancestors lived on beaches (were many of the rift valley fossils are found today) and when a lion came they could run into the water (or climb a tree), and when a crocodile or hippo came they could run onto land (or climb a tree) – if both occurred they picked up a stick and hit the animal on the head. The chimp’s ancestor stayed in the tree – our ancestor came down to the water. This wasn’t just a temporary occurrence – it was permanent and hasn’t stopped. We still prefer to live near the water any where on the planet and prior to agriculture we were all fishers. Also, you say that our hominid ancestors were too wimpy to fight off these big animals; if this is true, then how did they fight off all the predators on the savannah (lions, leopards, cheetahs, hyenas, hippos, black rhinos, wild dogs)? The animal threats on the open savannah are much harder to avoid than in the riparian forest where you can swim or climb a tree.
Our biology and behaviour (synecology) is easily explained by evolution in the riparian ecosystem.
Water is a key element in our culture and likely our evolution – failing to recognize the huge amount of evidence supporting this hypothesis is … wrong.
Ask yourself how is it that humans now easily occupy the richest ecosystems in Africa – the riparian ecosystems – and did it happen long ago? Is it also not true that humans can swim and hold our breathes easily whereas the other great apes can’t. The seafood available in the littoral also provides the nutrients and protein for big brains without the use of fire, a serious bottleneck to the evolution of our big brains as has been stated by Kate Wong (she mentioned that human babies need a very nutritious diet to grow big brains). A subcutaneous fat layer is non-existent in any purely terrestrial mammal and only occurs in animals with an aquatic habit – all the purely terrestrial animals (regardless of size) are hairy (giraffe, buffalo) and all the hairless ones are aquatic, semi-aquatic or had aquatic ancestors. If big equals hairless why not all animals our size and bigger and why not giraffes and buffalo?
Sure we dominated the savannah but not first – the best ecosystems in Africa and the world are the riparian and we are successful because our ancestors learned to dominate them – and we have never stopped. We then moved out from their with tools and bigger brains that allowed us to deal with the harsher environments in the savannah and later in the north and the rest of the world. The most successful humans as far back as we can look are beach/river/littoral dwellers and it is likely we always have been since our ancestor decided not to live in a tree anymore.
There is no reason why our evolution would be completely different than the other animals – a visit to Africa reveals the importance of the riparian ecosystem in the continued success of all the dominant organisms, including humans, and the evolutionary driver that ecology specifies.
Colin Buss
Campbell River
BC Canada
Dear Ms. Jablonski,
Reply | Report Abuse | Link to thisI’ve just read your article in Scientific American – “The Naked Truth”. You are probably wrong.
It is unlikely we became hairless because of the heat – no other terrestrial mammal has done that; none of the animals living on the savannah. As you say, it is apparently paradoxical that hair on our heads cools us (p 48) – exactly! It isn’t a paradox at all. That’s why all the animals that live full-time on the savannah have hair! The hairless ones, though big (elephant and rhino), also both have semi-aquatic ancestors (ask any paleontologist) or are currently semi-aquatic (the hippopotamus). And yes, over-heating is a problem but they use water to cool down – elephants hang out in watering holes as do rhinos, and hippos spend the day in the water. To say they are hairless without mentioning water is specious. It is also likely the main reason we’re hairless.
Also, only a minority of semi-aquatic mammals (seals) are haired – most are hairless. The hairy ones tend to live in cold climates where it is cold out of the water.
You re-iterate the theory that climate change forced our ancestors onto the savannah – this is an old hypothesis but has no supporting evidence and is counter to the behaviour of all other animals. Such conditions were (and are) more likely to force hominids to stream and lake banks where all animals go today when it is dry. Running away from water is not a good survival strategy or, therefore, an evolutionary advantageous action as is proposed by the savannah theory. The savannah theory is an old but ground-less hypothesis created when scientists had very little knowledge of synecology.
And not all carnivores roam about for their food. Lions, for example, mostly steal it from other predators, and all the big cats just wait for a herd of bovidae to wander by – very limited chasing is required on the savannah – ask a cheetah. Early hominids could have easily lived off food in the water, a more nutritious, easier to catch, easier to prepare food source.
Fact is, increased roaming by our ancestors is pure speculation and counter to the behaviour of other predators.
The aquatic ape theory is goofy but a better explanation exists that incorporates the idea of an aquatic background without the weaknesses of AAT: the multi-habitat amphibious theory. That is, our ancestors lived on beaches (were many of the rift valley fossils are found today) and when a lion came they could run into the water (or climb a tree), and when a crocodile or hippo came they could run onto land (or climb a tree) – if both occurred they picked up a stick and hit the animal on the head. The chimp’s ancestor stayed in the tree – our ancestor came down to the water. This wasn’t just a temporary occurrence – it was permanent and hasn’t stopped. We still prefer to live near the water any where on the planet and prior to agriculture we were all fishers. Also, you say that our hominid ancestors were too wimpy to fight off these big animals; if this is true, then how did they fight off all the predators on the savannah (lions, leopards, cheetahs, hyenas, hippos, black rhinos, wild dogs)? The animal threats on the open savannah are much harder to avoid than in the riparian forest where you can swim or climb a tree.
Our biology and behaviour (synecology) is easily explained by evolution in the riparian ecosystem.
Water is a key element in our culture and likely our evolution – failing to recognize the huge amount of evidence supporting this hypothesis is … wrong.
Ask yourself how is it that humans now easily occupy the richest ecosystems in Africa – the riparian ecosystems – and did it happen long ago? Is it also not true that humans can swim and hold our breathes easily whereas the other great apes can’t. The seafood available in the littoral also provides the nutrients and protein for big brains without the use of fire, a serious bottleneck to the evolution of our big brains as has been stated by Kate Wong (she mentioned that human babies need a very nutritious diet to grow big brains). A subcutaneous fat layer is non-existent in any purely terrestrial mammal and only occurs in animals with an aquatic habit – all the purely terrestrial animals (regardless of size) are hairy (giraffe, buffalo) and all the hairless ones are aquatic, semi-aquatic or had aquatic ancestors. If big equals hairless why not all animals our size and bigger and why not giraffes and buffalo?
Sure we dominated the savannah but not first – the best ecosystems in Africa and the world are the riparian and we are successful because our ancestors learned to dominate them – and we have never stopped. We then moved out from their with tools and bigger brains that allowed us to deal with the harsher environments in the savannah and later in the north and the rest of the world. The most successful humans as far back as we can look are beach/river/littoral dwellers and it is likely we always have been since our ancestor decided not to live in a tree anymore.
There is no reason why our evolution would be completely different than the other animals – a visit to Africa reveals the importance of the riparian ecosystem in the continued success of all the dominant organisms, including humans, and the evolutionary driver that ecology specifies.
Colin Buss
Campbell River
BC Canada
I remember Morgan well. That was about 40 yrs. ago. What we know from the fossil and genetic record has changed quite a bit since then. Morgan did not suggest an aquatic life, but a life along the shores of the great inland lakes that existed in Africa at the time. So perhaps it was a semi aquatic life. The other mammals that share almost hairless bodies are elephants and pigs. But, pigs don't sweat, nor do elephants. The pigs cool themselves by wallowing, the elephants with their great ears. Both these species do seem to follow the semi aquatic model, and Morgan talks about them as examples. But humans sweat! Profusely. Why would a semi aquatic mammal need to sweat? The marathon hypothesis seems to answer that. The cursorial hunter can run down even the swiftest prey. The prey animal soon overheats, and exhausts itself, while the human just keeps plodding on. This is how pygmies hunt down giraffe. The solution to this seeming contradiction? An early Hominid species did spend some time around the sea and the inland lakes. There they evolved a more upright posture, and became bipedal. Changing climate in Africa dried up most of the inland lakes, and the early hominids had to adapt to the dryer hotter environment. The ones that could still sweat adapted, the ones that couldn't died out. That's evolution. This whole time, this line wasn't much different from the other great apes, with about the same brain as a chimp. Eventually though, one line developed into the early
Reply | Report Abuse | Link to thisA. afarensis which was clearly bipedal 3.5 mil yr. BP and possibly well on the way to hairless. The other problem with the Morgan hypothesis is that there really is no fossil evidence to support her theory. Perhaps this period of living at the sea predated A. afarensis? I'm willing to entertain that. But, think the greater evidence points to the cursorial scavenger of the savanna as the most recent ancestor of modern humans. How this relates to the evolution of intelligence is more complicated. Nakedness and bipedalism combine tallow the early proto humans to carry tools, digging sticks, or hand axes, and other pebble tools with them as they forage and hunt. Along with the evolution of tool use was an evolution of culture and language. You needed to pass that information to your offspring. The more complex culture required more complex language, which required a larger brain, and so on. So arguably, it was the evolution of culture and language and a complex social environment that spurred the modern human more than nakedness.
Good comments--all. I've enjoyed most of 'em. Even the double posts!
Reply | Report Abuse | Link to thisBut, please don't forget about:
WAXING.
The opponents of Sahelanthropus as a hominin have yet to present a serious paper detailing their opposition. They have done a lot of speculating, however. But the craniodental morphology of Sahelanthropus has been clearly radically modified in the hominin direction.
Reply | Report Abuse | Link to thishttp://newpapyrusmagazine.blogspot.com/1999/01/our-earliest-african-ancestor.html
The human kidneys have been radically modified to enhance salt excretion. That's the function of multiple medullary pyramids within the kidneys of mammals. And this is the first time this has occurred in the 4o million year plus history of catarrhines primates. All other catarrhine primates have unipyramidal kidneys including the great apes. So why would humans be the sole primate to undergo such a radical modification of their kidneys?
Reply | Report Abuse | Link to thisAnd this is no minor anomaly. Humans on average have 8 to 18 medullary pyramids in their kidneys while other monkeys and apes have none. So there was obviously intense selection pressure in human ancestors to dramatically increase the number of medullary pyramids in their kidneys.
I should also note that the earliest fossil bipedal hominoid, Oreopithecus (7.6 million years ago), is found in aquatic environments-- in such huge numbers that it has long been speculated that this bipedal ape specialized in feeding on aquatic plants.
Marcel F. Williams
Hairless? Hardly.
Reply | Report Abuse | Link to thisTake one of your small kids, or the small kid of a good friend and take a close look at their skin. With the exception of the palms of the hands and the soles of the feet you'll note small, fine hairs everywhere. And I do mean everywhere.
Humans are just about as hairy as most other mammals, we just appear hairless because most of our hair is fine and light. This light hair letting the skin show through. It is not a matter of our losing our hair, but of our hair growing, well, thinner.
The problem with the aquatic ape scenario is that humans are the wrong shape. Too much surface area for our volume, which means we lose heat swiftly in water. The subcutaneous fat rationale doesn't work because subcutaneous fat is not found in all individuals, but is an adaptation to very cold climates.
Reply | Report Abuse | Link to thisThe kidney adaptation you mention also fits arid clime animals. With sparse and brackish water it helps to have an efficient way of removing salts and minerals. The great apes live in well watered areas, so they don't have to worry about it.
We are adapted to living in arid and semi-arid regions. Even our sweat is adapted to arid and semi-arid climes. Our proportions, kidneys, sweat, even the distribution of our fat deposits and their composition all point to a dry land origin. The aquatic ape theory is a romantic fantasy, but that's all it is.
Reply | Report Abuse | Link to thisYouve been duped!
Sweating is a post-evolutionary adaptation not the reason for human hairlessness. If it was, why have no other animals in Africa done this? All the currently hairless animals have aquatic pasts (elephant and rhino good evidence for this and it is repeated constantly in the literature), currently use water (water holes and rivers) or are semi-aquatic (hippopotamus). Sweating is like tool making. It was evolved to compensate for no fur like the opposable thumb allowed us to be more dexterous (it didnt evolve to permit primates to make tools). As the author says hair (fur) on the head is there for cooling (page 48). Sweating is also wasteful of water something most animals cant afford unless you live near the water and have adaptations to permit this. That is, you are big (elephant) or dangerous (hippopotamus) or smart (hominids).
All the furry animals (the vast majority) in Africa dont use sweating to cool because they dont need to. Why not hairless giraffes or buffalo? Of course wet fur is a maladaption but then how did the intermediate form of hairy, sweaty hominid survive?
As the author says, the body mass ratio of small animals makes their thermo-regulation difficult. The opposite is true for big animals.
The fact is there is little evidence to support any theory of the causation of human evolution. Hence, the best way is to use analogues. That is, how do other animals behave and what is the evolutionary pathway followed by extant mammals in Africa where hominids did the bulk of their early evolution.
Fact is, no animals who live and have evolved on the savannah have become fully biped, hairless apes. A very similar organism the baboon lives on the savannah and is hairy and four-legged.
Humans are today a multi-habitat, intelligent, tool maker that can kill any other animal and live where ever we like. Our closest relative, the chimpanzee has none of these adaptations. The question is, when did we become like this? Was is 200 000 years ago when the fully modern homo sapien first appeared? If so, did we lack all the behaviourial and synecological characteristics we now have and just pick them up? That is unlikely. What is more likely is our current apaptation drove our evolution and are the end result of six million years of learning how to dominate the best ecosystems on the planet the riparian/littoral stream and forest.
A theory that much more clearly matches the analogies is the multi-habitat, amphibious theory formulated by Andrew Lewis in Great Britain.
Paleoanthropologists need to learn humility. A theory such as the savannah theory is not supported by evidence and is counter to the evolution of all other animals in Africa. Until there is proof, we should realize there is no way to know absolutely.
Your sub-title suggests new evidence. What new evidence? There is none it is simply a re-hashing of an old idea promulgated when scientists had little knowledge of synecology the interaction of organisms with their environment. We now know the evolutionary drivers for many species there is no reason to believe humans were much different.
Colin Buss
Campbell River
BC Canada
I'm not saying the AAT is right - only that the analogies all point to semi-aquatic habitats no desert. The desert animals have hair.
Reply | Report Abuse | Link to thisSure we have evolved to survive in deserts but we've also evolved to live in the artic, mountains, farms, cities, and so on. We are a multi-habitat organism with the ability to adapt to any environment. Just because we live in cities now doesn't mean we became like we are because of that and the same holds true for the savannah.
It isn't about the existence of hair follicles - no one is debating that. It is the fact that a dog has a coat of fur and I don't. Genetic drift? Perhaps, or selection driven by the need for speed in water (like all other hairless mammals) post evolutionarily adaptapted to produce sweat to deal with heat for an animal that had access to plenty of water.
Reply | Report Abuse | Link to thisThis is great! Nice way of explaining the evolutionary advantage of hairlessness. The semi-aquatic theory is also well supported by the various analogues throughout the planet - with some minor exceptions, all hairless mammals have aquatic pasts. And we can swim and hold our breathe!
Reply | Report Abuse | Link to thisLucky me, my three chest hairs make me fairly well evolved. Pity about my huge eyebrows. Where does that leave me?
Reply | Report Abuse | Link to thisThat's wrong. Why only some hairlessness then and why have no other savannah dwellers done it. The point is none of the hairless mammals have no aquatic past.
Reply | Report Abuse | Link to thisThat is wrong. All the savannah animals have hair. Why if it is such a problem for over heating?
Reply | Report Abuse | Link to thisNOt an issue in this debate - controlled fire didn't occur until 500 000 years ago - potentially long after hairless ness evolved.
Reply | Report Abuse | Link to thisNOt sure where you got your facts but it is the corollary that is not true - savannah dwelling organisms are not hairless and the only ones who are have aquatic pasts or use water today.
Reply | Report Abuse | Link to thisAll the whales, most of the seals and so on are all hairless - lot more than three species. The hairy ones also tend to live in cold areas.
But clothing is probably a later adaptation of a tropical hominid that new how to make tools - changes in hair and fat in todays races could have evolved in the last 60 000 years since we left Africa. The key point is this - do hunter-gatherers in Africa wear clothes?
Reply | Report Abuse | Link to thisA big problem with paleoanthropology is it encourages speculation. Fact is, there is very little evidence for the evolutionary factors that drove our evolution. Further, because of this void scientists in this field often speculate.
Reply | Report Abuse | Link to thisWe do have some tools today to firm up the speculation; these are the knowledge of synecology from all animals. That is, how organisms are adapted to their environments.
The existing speculation is that the savannah environment enduced evolution in our species. This is not supported by our current knowledge of synecology but is an hypothesis that filled a void, so to speak, which scientists abore.
Leaving the beach for the desert is not a smart move and will get you killed - it will today and it is likely the same synecological dynamic existed six million years ago. The beach has better food and numerous avenues for predator avoidance for an increasingly smart ape.
At some point hominids learned how to be smart and dominate the best ecosystems on the planet. Did this happen 200 000 years ago once we had, against all odds, evolved water-wasting, food-wasting behaviours. Or did we always do this and therefore, much less parsimoniously, gradually evolve to reflect our new, luxiourous home?
the theory of evolution is not about being the storngest anymore,It s about being the most functional..because these two are not always comparable.the first one is more relative.
Reply | Report Abuse | Link to thisthe theory of evolution is not about being the storngest anymore,It s about being the most functional..because these two are not always comparable.the first one is more relative.
Reply | Report Abuse | Link to thisFirst of all, thick subcutaneous fat is maladaptive in an arid environment but highly adaptive in a coastal marine environment. Secondly, xeric animals like camels with medullary pyramids consume plants with a salt content higher than sea water. Camels also eat sea weed in north Africa which has a salt content equal to that of seawater. But there's no evidence that humans were confined to deserts and forced to eat salty terrestrial plant life in order to survive. All members of Homo appear to have been ominivores and earlier hominins such as the australopithecines tended to eat fruits, nuts, freshwater sedges and tubers.
Reply | Report Abuse | Link to thisSome of them girls on the 'net are completely hairless. I guess they have evolved into higher beings. Thus, porn stars are super-humans on the cutting edge of humanity. We should be more like them to improve as a race. Sure beats catching on fire!
Reply | Report Abuse | Link to thisDevolved from the eybrows up? Just a thought...
Reply | Report Abuse | Link to thisA shaved beaver is still a beaver, and a lipstick wearing pig is still a pig. No evolution is required, just as in your Lamarkian comment...
Reply | Report Abuse | Link to thisI'm really more like tha Walrus...
Reply | Report Abuse | Link to thisBaboons that live near the sea will eat mussels, limpets and crabs. Humans, unlike other marine mammals, must have a source of fresh water to survive. The semi-aquatic adaptations must certainly have come from riparian zones, and vast shallow inland lakes and riverine systems not unlike the Amazon Basin today, which is mostly under water half the year, rather than an actual marine environment. If you were a bipedal tree dweller in such a forest, you would have to wade and swim quite a lot. Undoubtedly the early homonidea speciated quite a bit and filled as many niches as they were able. Up until about 3 mil. yr. BP there were quite a few different species of bipedal hominids about. Eventually though they all died out. Why would that be? Certainly in all the vastness of the wild Earth at least one species of bipedal ape would have survived besides humans. Nope. Didn't happen. People ate them all, just like the Walrus and the Carpenter, and the Oysters... OOOH! A bipedal hominid, a marine mammal, and a benthic bi-valve all in one poem!
Reply | Report Abuse | Link to thisWhy is having a hard time to accept that humans are a different species from monkeys? They look like them BUT they are not monkeys?
Reply | Report Abuse | Link to thisWho said that we are not hairy? There is hair even where the skin looks totaly bare. Genetically we are just as hairy as apes. Desmond Morris should have set at least the title of his book right. Look closer!
Reply | Report Abuse | Link to thisEver been to Provincetown during Bear Week? There's still hair out there.
Reply | Report Abuse | Link to thisTonyJCarey – I'm just a bystander to this seemingly raging debate, but you seem to have identified several very good points – good luck with your paper.
Reply | Report Abuse | Link to thisI'm also innocent of any mathematician charges, but your mention of the Toba event made me realize that in a small population pool any random genetic mutation would have a greater probability of being promoted than would the same single mutation occurrence in a larger population, especially if it produced a neutral benefit to selection. This should already be well known among geneticists, but could be highly significant for traits that evidentially develop coincidentally with a population bottleneck.
Being an almost hairless Scandinavian - I used to explain my lack of bodily hirsute-ness as me being further removed from the ape than my hairy peers. I was 17 when I came up with this feeble rationale - mainly because I envied my hairier pals. One reason for our lack of thick body hair is that it enables sweat and therefore rapid cooling after exertion which is essential for max. brain and body function. Come winter my ancestors slaughtered furry mammals to stay warm - today my outer winter ensemble is largely synthetic - so petroleum is the new 'hair' and it works.
Reply | Report Abuse | Link to thisWhy does the hair on our face and head continue to grow and need trimming?
Reply | Report Abuse | Link to thisAgain, humans have multipyramidal kidneys that are capable of excreting urine with a salt concentration up to 3.6%. The salinity of the world's oceans are about 3.5%. Humans also produce significant quantities of hypotonic metabolic water. Humans also excrete salt through their eccrine sweat glands. The precursor fluid of human sweat is actually isotonic relative to the human blood stream. However, humans today excrete sweat that is hypotonic relative to the blood stream because the sweat glands are permeated a venous system that actually returns salt back to the blood stream. That's because in an inland environment, loosing to much salt from the body can be deleterious to human health. That fact that a significant number of human corporeal sweat glands are non-functional indicates that there has been strong selection pressure in modern humans to reduce salt loss. This strongly suggest that human ancestors use to occupy an environment where excreting substantial amounts of salt was essential to their survival. So this is indicated by both the kidney morphology and by the active and substantially increased eccrine sweat glands in humans relative to other primates.
Reply | Report Abuse | Link to thisMarcel F. Williams
Long beards along with thick chest hair are thermal adaptations (biological scarves) for men adapted to colder environments. Women have approximately twice the subcutaneous fat as men do, especially in the chest area, so they used fat to reduce thermal stress in cold environments. Carrying too much fat would have also reduced the running ability for male Pleistocene European hunters.
Reply | Report Abuse | Link to thisLong head hair is a maternal adaptation. But since I'm going to be publishing a paper on that subject, I really can't discuss it in detail on this forum:-)
It's funny how we evolved so differently from other animals. Our survival nowadays depends on our mental capacities of rationalizing, analyzing and solving problems. As a result we don't have the finely tuned senses or physical protection most animals do have.
Reply | Report Abuse | Link to thisIt's practically impossible for a human nowadays to go live in the wild without any tools or provisions. Somewhere that's kind of sad.
Wonder how we would have turned out had we not chosen for the brains.
Humans are tool dependent creatures. And its been that way for Homo for at least 2.6 million years. Its enabled us to live in practically any region on Earth. And it will probably enable us to live anywhere in the solar system and perhaps, someday, anywhere in the galaxy!
Reply | Report Abuse | Link to thisMarcel F. Williams
Marcel – Great info on human evolution, but before more readers get real excited about living on some other planet, even Mars would require a lot of teraforming to, among other things, give it a magnetic field that could protect us from solar radiation and cosmic rays, or at least some really strong local generators. Otherwise we’d have to accept a much higher rate of really random evolution.
Reply | Report Abuse | Link to thisAll you need to protect yourself from galactic radiation and major solar storm events is 5 meters of water. So all you need is a pressurized plastic dome beneath a transparent 5 meter thick plastic dome of water. However, intense ultraviolet radiation would a problem on Mars since there's no ozone layer. But transparent plastics that shield against UV rays have already been developed.
Reply | Report Abuse | Link to thisEach pressurized biodome could probably be 100 to 200 meters in diameter or more and 50 to 100 meters high.
IMO, 200 years from now, most people will live in titanic rotating solar orbiting worlds with Earth-like interiors (sunshine, clouds, lakes, forest, grass, beaches, etc.) while most of the Earth will be returned to its natural state for ecotourism.
Marcel F. Williams
Good job, however, the accumulation of less protected exposure to 'normal' radiation should produce a higher incidence of genetic mutation, if not fatal cancers. An optimist can hope that would produce the next thing in intelligent life. I’m more of a realist: if we can't make for the long term on Earth, we're not likely to make it anywhere else and certainly wouldn't have earned the right to destroy another planet.
Reply | Report Abuse | Link to this5 meters of water is all you need for radiation protection equal to that of living in the State of Colorado. You would, however, be temporarily exposed to more radiation once you left the habitat. But people experience temporary exposures to higher levels of radiation all of the time on Earth. If you work at a nuclear plant, nuclear submarine, or nuclear aircraft carrier, get a chest X-Ray, or fly in an airplane!
Reply | Report Abuse | Link to thisMarcel F. Williams
Marcel – Once again you make good points, but to fairly assess the risk factors in each environment would require a more detailed analysis than I can make at this time.
Reply | Report Abuse | Link to thisMy primary objection to lofty goals for migrating humanity to other worlds is that survival on this one is not yet acknowledged as our most important mission. If we discontinue the overpopulation and consumption of this planet, I’d have no objection to adventurers traveling throughout the cosmos, as long as that didn’t threaten the survival of humanity on Earth.
Too often migration is considered to be the (too) long term solution to our destruction of the Earth. If achievable, that plan would fine, too, if it weren’t for the billions left to suffer on Earth. At this point I think we should be focusing on job #1.
The Earth is a planet designed to accommodate about 10 to 20 million hunter-gathers. We surpassed that a long time ago. And our population may continue to grow until we've passed over 10 billion people.
Reply | Report Abuse | Link to thisNow we've discovered that we're living on borrowed time thanks to the fact the Earth is periodically hit by multi-kilometer in diameter asteroids which can cause mass extinctions on a global scale.
And today, only two nations have enough nuclear weapons to wipe out the entire human species. But by the end of the century, the US and Russia may be joined in that destructive capacity by Europe, China, Japan, India, Israel, Pakistan, and maybe a few others.
The human species is taking a very big risk by continuing to place all of their eggs in this one fragile basket called Earth!
Marcel F. Williams
Whenever we lost our fur, the change also demanded the addition of a very important tool, the baby sling. It's very difficult to go camping, say, with a new baby without a good baby sling. And making one is not that simple. Did that help our brains evolve?
Reply | Report Abuse | Link to thisElaine Morgan answered this question in "The descent of man". It is the same answer as Desmond Morris - I dont know who came first.
Reply | Report Abuse | Link to thisElaine Morgan explained this in "The Descent of Man". It is basically the same answer as Desmond Morris - I dont know who came first.
Reply | Report Abuse | Link to thisI found this article unsatisfying. I is poorly written and seems intended to refute the aquatic ape hypothesis. However, in light of the recent articles on Ardi, this articles reliance on the savanna theory of human evolution puts it on the scrap heap of scientific inquiry as it is published.
Reply | Report Abuse | Link to thisDidnt Dawkins suggest that we are hairless because of sexual selection? Skin colour demonstrating the health of the individual?
Reply | Report Abuse | Link to thisRe sparkie:
Reply | Report Abuse | Link to thisI just read this part in Dawkins' The Ancestor's Tale. He believes that sexual selection is why human became hairless (also bipedal and have bigger brain). But I doubt the use of sexual selection as the solution to any mystery we can't solve, just by saying that "females/males happen to like that, dunno why".
I believe sexual selection could only be an *amplification*, not the *cause* of a particular adaptation. Even in the case of the spectacular tail of the peacock, I believe it's a pre-adaptation -- it has some practical use in the past, we just haven't find out.
On the other hand, "demonstrating health through skin color" is much more reasonable.
It's probably the most likely reason. After all many other species have gone through difficult conditions, but only ours survived by stealing the skins of other creatures because our own could not keep us warm-
Reply | Report Abuse | Link to thisThis article claims that AAT is untenable for 3 reasons, here are some thoughts:
Reply | Report Abuse | Link to this1. "Aquatic mammals themselves differ considerably... no simple connection between hairiness and the environment."
-- AAT actually provides systematic explanation for why some aquatic mammals are naked, some are not (big-to-medium sized = naked; small sized or Arctic = haired), in contrast to somehow naive version in the article (big sized doesn't mean naked, e.g. bears; all running animals have fur, humans can't be an exception).
2. "Watery habitats were thick with hungry crocs and aggressive hippos."
- In fact, speedy predators in grassland (lions, tigers) are far more deadly than slow crocs and herbivorous hippos. Which habitat has a higher survival rate for humans? Also, every habitat has its own top predators, you have to face them anyway.
3. "AAT is overly complex ... the simplest explanation is usually the correct one"
- So Einstein's relativity is overly complex comparing to Newton's gravitation laws, does it mean relativity should be wrong? i.e. before saying which theory is simpler, first judge which one is more powerful.
I am a gorilla. The following point of view is coming from a supposed "human" that is covered with hair. Seriously, My body is covered in hair and if I didn't trim it, some hairs would grow at least 2 inches long. It sucks. I saw this mag at a local grocery store and read a little of it. I had to look the website up and respond. Maybe I'm not the evolution type, but I want to become one with the humans. If your going to offer info on the evolution of a hairless man, please offer some concrete permanent solutions to help us neanderthals become one and catch up with civilization. I want so much to be able to frolic at the beach without a shirt. I am too afraid of being shunned and forced to cover my hair shirt. Please, I need a solution for a hairless torso, and don't respond with the usual electrolysis that doesn't work. Also, lest we forget the silly laser hair removal that is neither "permanent" nor "semi-permanent". It's a shill to take money from needy desperate primates who just want to fit in. I WANT ANSWERS! I WANT A SOLUTION! PLEASE HELP! I don't want a temporary laser hair removal fix that lasts 2 weeks, I want a permanent solution. I have suffered this torment for over 17 years and I have scoured the lands in search of this grail and like U2- I still haven't found what I'm looking for. Please forward this to the powers that be and help me become one with my fellow hairless shoulder, chest, abs, back human beings.
Reply | Report Abuse | Link to thisI am a gorilla. The following point of view is coming from a supposed "human" that is covered with hair. Seriously, My body is covered in hair and if I didn't trim it, some hairs would grow at least 2 inches long. It sucks. I saw this mag at a local grocery store and read a little of it. I had to look the website up and respond. Maybe I'm not the evolution type, but I want to become one with the humans. If your going to offer info on the evolution of a hairless man, please offer some concrete permanent solutions to help us neanderthals become one and catch up with civilization. I want so much to be able to frolic at the beach without a shirt. I am too afraid of being shunned and forced to cover my hair shirt. Please, I need a solution for a hairless torso, and don't respond with the usual electrolysis that doesn't work. Also, lest we forget the silly laser hair removal that is neither "permanent" nor "semi-permanent". It's a shill to take money from needy desperate primates who just want to fit in. I WANT ANSWERS! I WANT A SOLUTION! PLEASE HELP! I don't want a temporary laser hair removal fix that lasts 2 weeks, I want a permanent solution. I have suffered this torment for over 17 years and I have scoured the lands in search of this grail and like U2- I still haven't found what I'm looking for. Please forward this to the powers that be and help me become one with my fellow hairless shoulder, chest, abs, back human beings.
Reply | Report Abuse | Link to thisHow long do the sea mammals get convergence of their fins ? In the fin, they records that it had fingers as bones. While the dolphin cannot bend its fin, the seal can bend,crawl and has nails. Both of them are no fur, both waists are straight. The difference might be convergence time. Our waist is although straight, most of us does not have strong arms and cannot creep over the ground. We have to stand up on the ground. Though, most of us does not have swift thigh. Lion will easier catch us in the savanna. Going to aquatic, first, it may be lose fur, get the straight waist to swim. Second, other convergence may occur. Ancestor did not confuse and blushed when they looked at other apes have rich fur ? they had not escaped from the aqua before convergence ? After regained the ground, did ancestor restart the evolution and the history without fur ? We are right in the evolution. we may regain rich fur...
Reply | Report Abuse | Link to thisScientific American February 2010
Reply | Report Abuse | Link to this“The Naked Truth” Nina G. Jablonski
Do not dismiss Elaine Morgan too lightly.
Dr. Jablonski’s well-documented study has a side bar “Why the Aquatic Ape Theory Doesn’t Hold Water”. The side bar states “the simplest explanation is usually the correct one”. However, there is another widely accepted criteria, that a single theory that explains many observations is preferred over a theory that explains only one of those observations. Dr Morgan explains not only the loss of hair but also language (hunters gesture, fishermen shout), and gender specific features. Far from being prey to the hungry crocodiles and aggressive hippopotamuses, aquatic humans would lasso the dozing crock and say to the hippo “chase us and we will trap you, flee from us and we will eat the slow ones”.
Gordon Riel
1210 Bay View Ct.
Edgewater, MD 31037-4313
Hello
Reply | Report Abuse | Link to thisBesides humans having no fur, what about our noses. Are we the only ones that have a nose that points downward in the animal kingdom? Is it for better sight. Maybe when standing above the grasslands we need to smell downward. You don't want to look up someones nostrils when you talk to them?
does anyone know the volume number to this issue of the magazine, february 2010? i am doing a project on this article and need to know the volume number of the magazine it is in.
Reply | Report Abuse | Link to thisAlthough I found Nina Jablonski's article reasonable I do note that one clear and demonstrable function of body hair remains unexamined and neglected; it's function as part of our sensory system. Other's may consider their body hair superfluous but mine continues to function exceptionally well as an extension of my sense of touch; it can detect the presence of insects and parasites that completely hairless skin cannot (as an admittedly anecdotal personal example - a toxic paralysis tick making it's way up my leg recently was only felt because the creature brushed against hairs and I was able to remove it before it had burrowed into my flesh).
Reply | Report Abuse | Link to this�Anyone who doubts that hair has a role in touch sensitivity ought to try this simple experiment; take a single fine hair from a comb or brush and compare what you feel when it is brushed over completely hairless skin and over body hair. You will be unlikely to detect the former and will clearly sense the latter. I admit many people may consider the complete loss of body hair to be advantageous for social reasons or even an advantage to avoid the annoyance and irritation that it's sensitivity� contributes to the presence of insects but in evolutionary terms I suggest that it's better to be aware of the presence of insects, even if annoying, than to be unaware of them.
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�I would also point out that hair extends touch sensitivity beyond the surface of the skin and note that during moments of fear when goose pimples occur, the hairs stand on end, extending touch sensitivity to it's maximum distance beyond the surface of the skin - more than 50mm on my admittedly hairy legs. I doubt that this is evolutionary coincidence; evolution may have favored less body hair but I would argue that there remained evolutionary reason to retain some as well as the capacity to stand it on end for reasons other than striking fear into predators. I'm not sure about moles but suspect that what hair they� retain has sensory functions also, and is particularly useful in complete dark underground.
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I'm not sure where the presumption of body hair having little or no purpose originated - others have failed to take consideration of the sensory function of body hair but I'm disappointed that it continues unexamined and that the author, by failing to recognise it, has effectively perpetuated it.
After reading this article, I think I got to reexamine my body again.
Reply | Report Abuse | Link to this<a href="http://legoarchitecture.org/">David</a>
Desmond Morris was quoting Elaine Morgan's "aquatic ape" theory. The usual disagreement is between that and the "savannah" theory, which says we lost our fur so we could adapt to hunting game on the African savannah (plains). I think there are a few holes in both of them. We are one of very few species (us and some salamanders!) that are neotenous, which means we are sexually mature in the juvenile form, i.e. we are like baby apes that can breed. That is something we know for sure and does explain our reduced body hair. The proper question then is why are we neotenous? Possibly to prolong development so as to grow bigger brains? D*mn*d if I know, LOL!
Reply | Report Abuse | Link to thisActually, that feature of our noses does fit with Morgan's aquatic ape theory, whether you buy into it or not.
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