Okay, so this is brining out my inner anthropology nerd. So you have been warned, primate rant to follow. And yes, I fully appreciate that Tarzan is a work of fiction, but interestingly, The Jungle Book has a somewhat better kernel of truth at the start of the story. There have been many cases of 'wild children' raised by animals other than humans, although some of these cases have turned out to be hoaxes. However, is has happened that young children have survived with wolves, and there are some cases where it appears they also survived with monkeys. Now to be fair to Edgar Rice Burroughs, he does say that the Apes that raised Tarzan are a species unknown to science, so wether they would be more Gorilla like or Chimpanzee like could be debated (and both are great apes). Gorilla's seem an unlikely choice to raise a human child, especially a male one. Gorilla's live in a harem society, with one adult male and lots of females. Young males are driven out as they approach adolescence. These young males then go out and try to find another harem with an aging male they can kill or drive out. When a male take over a harem he kills any baby males in the harem. Chimpanzees on the other hands are a whole other matter. Actually, there are too distinct species of chimpanzee. The bonobo, or pygmy chimpanzees are actually just a little bit closer to humans that the classic chimpanzees that you usually see used in movies and the like. The main difference between bonobos and the classic chimpanzee is in social behavior. As one professor I had put it, "The bonobos are the make love not war chimpanzees." Both kinds of chimpanzee live in large troops, but bonobo life is pretty much governed by sex. They use it for just about every social situation, including to resolve conflict. On the other hand the classic chimpanzee tends to be much more aggressive. Classic chimpanzee groups have been known to fight each other, and will also hunt and kill other monkeys for food. They are lead by an alpha male, and they tend to resolve things with violence. When you see a chimpanzee in the movies, it's almost certainly a classic chimpanzee, and is also not full grown. As smart as they are, they just become too aggressive to be used in movies. But, it is conceivable that either group of chimpanzee might raise a human male child. And since bonobos weren't really known about by Europeans until after the first Tarzan stories were written, maybe the bonobos are the Mangani group of ape's the Burroughs made up. Or, you know, it's fiction, maybe they are just a fictional group of apes that never existed at all. Okay, anthropology rant done.