Chimpanzees

"Just 6 million years ago, a single female ape had two daughters. One became the ancestor of all chimpanzees, the other is our own grandmother."

"The Cerebral Cortex is the surface region of the brain that is most strongly linked to intelligence. A human’s cerebral cortex, if flattened, would cover four pages of typing paper; a chimpanzee’s would cover only one page; and a rat’s would cover a postage stamp."

"Children, behold the Chimpanzee, He sits on the ancestral tree From which we sprang in ages gone. Im glad we sprang; had we held on, We might, for aught that I can say, Be horrid chimpanzees today."

"Studying chimps ‘has helped me to realize, perhaps more than anything else, just how different we are from them’."

"Humans have more sympathy. In the chimp you have sympathy between a mother and a child but you seldom find it anywhere else. Sympathy is a very, very human characteristic."

"The human brain is composed almost exclusively of the [cerebral] cortex. The brain of a chimpanzee, for example, also has a cortex, but in far smaller proportions. The cortex allows us to think, to remember, to imagine. Essentially, we are human beings by virtue of our cortex."

"If chimpanzees can experience loneliness and mental anguish, it becomes more wrong to use them for experiments in which they are isolated and anticipate daily pain."