Fifty years ago Jane Goodall entered Tanzania's Gombe Stream Game Reserve to study wild chimpanzees. Scientific American's Kate Wong recently called Goodall to ask her what she has learned from observing our closest living relatives. Excerpts from their conversation appear in this December 2010 Q&A. Additional commentary from Goodall follows below, including answers to questions posed by Scientific American readers on Facebook.

SA: John R. Harris asked via Facebook whether you have seen any behavior in primates that could shed light on the commonality of ritual music and dance in humans. Do you think these behaviors or some precursors were present in a common ancestor, or are they unique to the human lineage?

: Chimpanzees often perform amazing rhythmic displays, almost like dancing, when they come upon a waterfall way up in the mountains [in Gombe] that drops 80 feet onto a stony streambed and makes a roaring sound. The chimpanzees' hair will stand on end and then they start this rhythmic swaying from side to side. It can last 20 minutes. Then sometimes at the end you will see them sitting and looking at the water, their eyes following it as it falls. If they could just talk with each other about the feelings that trigger these displays—which I believe must be something like wonder or awe—that could easily become a form of religion, the worship of the elements.

SA: Scientists often caution against anthropomorphizing any behavior seen in a particular animal. Is there a danger of going too far in the opposite direction, of putting human behavior in a completely different category from that of any other creature?

: We're so arrogant. We think everything we do must be of a different nature and a different order of magnitude; therefore, anything that looks like human behavior in animals obviously can't possibly be anything like ours. I was criticized hugely when I first talked in 1960 about chimpanzees having emotions and feelings and being able to think. Reasoning and emotions were supposed to be unique to us, as was personality. Fortunately, as a child I'd been taught by my dog Rusty that that wasn't true. Animals have moods—they can sulk, they can be happy, they can be sad. I knew Rusty could think, I knew he could work out problems. And he definitely had a very distinct personality, different from any other dog I've ever had. So even if you go way down the evolutionary scale, you find quite different personalities between members of the same group. Yet when I first talked about individual differences among the chimps, I was told by ethologists that, "Well, yes, maybe there are such things, but we don't really understand them, so we shouldn’t talk about them."

People who have pets know that animals have feelings and personalities and minds. Scientists look for the differences between humans and animals more than the general public does. Every time some discovery is made that challenges human uniqueness, there's a flurry of activity to try and find some other way in which we're unique. But it's a very blurry line that divides us from chimps.

SA: Virgilyn Abibas asked via Facebook whether you ever imagined Fifi and David Greybeard placing you under their own magnifying glass. What do you think they uncovered about you?

: That's the $10 million question—what did the chimps think of me? They accept humans. I don't imagine they think of us as being that much different from baboons or the other creatures that they share the forest with, although none of the other creatures they share the forest with follow them around. But beyond that I don’t know what they think of us.

SA: It took a while for them to accept you though, didn’t it? How did you put them at ease?

JG: I would sit on the ground and dig little holes or pretend to eat leaves—anything so that they didn't think I was interested in them, that I just happened to be there. I never tried to get too close too quickly. I spent a lot of time sitting on the Peak or some other vantage point, wearing the same colored clothes, and watching them from a distance. Then when there was a tree that was in fruit, and I knew the chimpanzees would come and feed on the fruit, I would build a little blind. They knew I was there, but it was a sort of unspoken rule that I would remain behind these palm fronds. Gradually they got more and more used to me and I could begin to actually follow them.

The infants are very curious, and in the early days, they were particularly curious. They knew that their mothers were still a bit apprehensive, but their curiosity overcame them. They would just reach out and touch me and then sniff their finger, because that's how they learn about things.

SA: Recently, archaeologists working in Ethiopia announced that they had found evidence that humans were using stone tools to butcher animals 800,000 years earlier than previously thought, and the hominids in question were probably australopithecines, namely Lucy's species, . The news made a big splash, but given what you've observed in chimps, is this evidence that primitive hominids were using stone tools surprising to you?

: No, I didn't think it's surprising at all, really. Chimps have been seen using sticks to kill bushbabies in a tree, sort of stabbing at them. They use rocks to break open hard-shelled nuts. It doesn't surprise me. The first tools that we used, or our lineage used, would have been not rocks, which are more complicated, but twigs and leaves and those kinds of things, I would imagine.