NO HEAD EQUALS DEAD?: Not in the case of the cockroach, which can live for weeks on a prior meal and breathes through its body parts.
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Cockroaches are infamous for their tenacity, and are often cited as the most likely survivors of a nuclear war. Some even claim that they can live without their heads. It turns out that these armchair exterminators (and their professional brethren) are right. Headless roaches are capable of living for weeks.
To understand why cockroaches—and many other insects—can survive decapitation, it helps to understand why humans cannot, explains physiologist and biochemist Joseph Kunkel at the University of Massachusetts Amherst, who studies cockroach development. First off, decapitation in humans results in blood loss and a drop in blood pressure hampering transport of oxygen and nutrition to vital tissues. "You'd bleed to death," Kunkel notes.
In addition, humans breathe through their mouth or nose and the brain controls that critical function, so breathing would stop. Moreover, the human body cannot eat without the head, ensuring a swift death from starvation should it survive the other ill effects of head loss.
But cockroaches do not have blood pressure the way people do. "They don't have a huge network of blood vessels like that of humans, or tiny capillaries that you need a lot of pressure to flow blood through," Kunkel says. "They have an open circulatory system, which there's much less pressure in."
"After you cut their heads off, very often their necks would seal off just by clotting," he adds. "There's no uncontrolled bleeding."
The hardy vermin breathe through spiracles, or little holes in each body segment. Plus, the roach brain does not control this breathing and blood does not carry oxygen throughout the body. Rather, the spiracles pipe air directly to tissues through a set of tubes called tracheae.
Cockroaches are also poikilotherms, or cold-blooded, meaning they need much less food than humans do. "An insect can survive for weeks on a meal they had one day," Kunkel says. "As long as some predator doesn't eat them, they'll just stay quiet and sit around, unless they get infected by mold or bacteria or a virus. Then they're dead."
Entomologist Christopher Tipping at Delaware Valley College in Doylestown, Pa., has actually decapitated American cockroaches (Periplaneta americana) "very carefully under microscopes," he notes. "We sealed the wound with dental wax, to prevent them from drying out. A couple lasted for several weeks in a jar."
Insects have clumps of ganglia—nerve tissue agglomerations—distributed within each body segment capable of performing the basic nervous functions responsible for reflexes, "so without the brain, the body can still function in terms of very simple reactions," Tipping says. "They could stand, react to touch and move."
And it is not just the body that can survive decapitation; the lonely head can thrive, too, waving its antennae back and forth for several hours until it runs out of steam, Kunkel says. If given nutrients and refrigerated, a roach head can last even longer.
Still, in roaches, "the body provides a huge amount of sensory information to the head and the brain cannot function normally when denied these inputs," explains neuroscientist Nick Strausfeld of the University of Arizona, who specializes in arthropod learning, memory and brain evolution. For instance, although cockroaches have a fantastic memory, "when we've tried to teach them when they had bits of them missing, it's hopeless. We have to keep their bodies completely intact."
Cockroach decapitation may seem macabre, but scientists have conducted many experiments with headless roach bodies and bodiless roach heads. Decapitating roaches deprives their bodies of hormones from glands in their heads that control maturation, helping researchers investigate metamorphosis and reproduction. And studies of bodiless roach heads shed light on how their neurons work. Plus, it provides just one more testament to the cockroach's enviable endurance.
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17 Comments
Add CommentOk so someone explain to me the difference between cutting off the head and sealing it in a jar and not cutting off the head and sealing it in a jar. We are talking starvation here correct? Soooo regardless of headless or not it would starve in the same amount of time... or will a cockroach eat itself if left with no other food?
Reply | Report Abuse | Link to thisIf they can spend money to study these gross, nasty bugs without their heads and bodies for, "helping researchers investigate metamorphosis and reproduction" and "studies of bodiless roach heads shed light on how their neurons work". Study them to find out how to erradicate them. I know they are resilent, but everything has its limit, we really need to find theirs. They are just gross and nasty and can really make you sick. UGH!
Reply | Report Abuse | Link to thisamynks70 ,
Reply | Report Abuse | Link to thisI am sure they feel the same way about you. I'll never understand the human need to eradicate what is different. It is a sign of both intellectual and social ignorance. Wanting them out of your house is one thing wanting them off the planet is another. They are here because they fill a niche that will just get filled by some other creature you'll probabably find equally gross.
I just cut of a head of a coackroach, not because of a science test but because I was pissed off at it, its the second night in a row i find one in my "I thought it was a very clean Kitchen", and I had to give an example here for the other roaches. After cutting it off i was amazed to see that both the head and the body did not stop moving, and I went online where I finally found this article. pretty interesting, Im still deciding on what to do next, maybe I will just see how long it will "live" in this state of headlessness.
Reply | Report Abuse | Link to thisRamon,
Bangkok Thailand
boy, I hope PETA doesn't see this article. Imagine the uproar. Decapitating helpless cockroaches. They have feelings too don't they. Ha Ha. I wonder what they are thinking when they see their own body detached from their head. To touch on Tobys question, I wonder if the head tries to eat the body?
Reply | Report Abuse | Link to thisi have good news for you amynks70, now we are pretty sure that we can't eradicate those horrible creatures by beheading each of them. let's try plan B, force them to eat uncocked macaroni with rotten tomato sauce.
Reply | Report Abuse | Link to thisi am really interested in something that i can't describe.
Reply | Report Abuse | Link to thisif both the head and the body can live separately, how can the creature "self" be ?
ok, i am not talking about a "soul" by the religious/philosophic sense, i know that by its decentralized neurosystem it doesn't have one single control unit and so no central thinking, but there must be something more like a "self" (let's not say "ego" as it would be far different from humans and primates), i mean something (material or not) that help to make decision, i mean one united decision that benefits of its sensory and actuators all around its body and head.
please, anybody have read any alike article please point me to it.
khaled.khalil[at]gmail.com
In spite of this article, I wonder if the roach could be fully functional if we put the head and body back together.
Reply | Report Abuse | Link to thisKhaled, I think I understand your thinking process, but look at it more like someone with a severed limb, what happens to their self? At this point isn't it more a matter of biology or even atoms now existing not as close to each other? I mean even with humans, brain isn't "necessarily" the sole center of the self, nor can we harm it even with physiological death, the essence is unharmed in all of these cases in my opinion and irrelevant to the article.
Reply | Report Abuse | Link to thisthe problem with PETA getting mad about this is that no one ever worries about the ugly animals. I mean, have you received anything in the mail that starts "Save the Oppossum"? Then again, look at the manatee...
Reply | Report Abuse | Link to thisThis has gotten me all inspired to pull out that old DVD of "Joe's Apartment", and watch it again tonight. I hadn't thought about it for years. I LOVE that movie, but for some reason, my wife and daughters refuse to join me in watching it..................
Reply | Report Abuse | Link to thisThanks TQ for bringing this tidbit of info into my life. And thanks Brenda for bringing this article unto my life. I can scratch this off the bucket list.
Reply | Report Abuse | Link to thisI just wonder what the point of this research is? It sounds very much like animal cruelty to me ... we don't treat criminals and child sex offenders like this and they wreak far more damage than cockroaches? This research is not curing cancer. It's not educating criminals how to behave better. It's not improving human life. It's not making the world a better place. A cockroach is still another living, breathing creature. I hope that when humans finally wipe themselves out the cockroaches have the last laugh.
Reply | Report Abuse | Link to thisI just wonder what the point of this research really is? It sounds very much like animal cruelty to me. It's not curing cancer. it's not educating criminals. It's not improving human lives nor is it improving the planet. I know it is definitive scienfiic research, but I don't believe it's valid or necessary. Cockroaches are still living breathing creatures - and what makes them gross? Nothing! They don't rape and kill children. They don't vent road rage. They don't steal, lie, and embezzel. They don't harm people at all - they don't even bite us. They just go about their business. And it turns out, that if they're in your kitchen you're really not that clean - you've left crumbs of something edible - so in fact you're really the gross one.
Reply | Report Abuse | Link to thisI just hope that when humans finally wipe themselves out that the cockroaches have the last laugh.
This is Like watching a Horror movie
Reply | Report Abuse | Link to thisIf you didn't find an answer yourself already: maby the 'self' part or awareness is in the head but as the article says if parts of the brain are removed their memory is not functioning properly anymore and I guess that counts also for it's awareness. Also it could be possible that if you split the brain in 2 parts there are two 'selfs' If you found out something more about this I'm interested to know: jaaaaaaaaaap@gmail.com (10x a)
Reply | Report Abuse | Link to thisThanks! Jaap
Turns out cockroaches have two brain one in the head and one the the tail. Since there is no need for two brains, the brain in the tail is used when the head, along with the other brain is cut off.
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