Narrator: This is Science Today. After the death of a beloved gorilla from a big city zoo, the body might wind up on Adrienne Zihlman's dissection table. It might be unromantic, but Zihlman, an anthropologist at the University of California, Santa Cruz, dissects these close relatives of humans because we don't know much about them.

Zihlman: Most of what we know about gorillas is from the skeleton and especially the dentition and the skull. And very little is known about the rest of the animal. So one reason for studying them is to look at the whole animal, look at the soft tissue as well as the bones.

Narrator: As Zihlman dissects her animals, she looks for clues as to how humans, gorillas and chimpanzees may have diverged from a common ancestor around five million years ago -- comparing things like the amount of muscle in the chest, arms and legs.

Zihlman: So the gorilla data can be compared to ourselves as well as to chimpanzees. So it really literally puts flesh on the bones, and you can get much more of a sense of the whole animal.

Narrator: For Science Today, I'm Steve Tokar.