25. A chimp named David Greybeard changed the definition of a human in 1960
Post-Darwin, scientists spent a lot of time trying to figure out how we differed from other animals. One of the most popular theories held that only humans could use tools. In 1960, a chimpanzee named David Greybeard blew the argument out of the water. The ingenious chimp flabbergasted famous primatologist Jane Goodall by using a grass stalk to extract termites from their mound. This proved to be the tip of the iceberg: Goodall witnessed the Gombe chimps make weapons and objects for grooming. David Greybeard transformed our understanding not only of chimpanzees but of human beings.