*inhale*
As a Christian, I don't believe this, but let me play Devil's advocate (pretend I do): According to the theory of evolution, Neanderthal man was the evolution right before homo sapiens. Neanderthals were short, broad, and had large muscles. They had very simplistic speech and high endurance, and survived off a diet composed primarily of meat. Neanderthals had a very different skull shape to homo sapiens, which Tarzan's physical features display (such as his pointed chin and large forehead). Neanderthal man populated the majority of Earth during the Middle Paleolithic era. Homo sapiens (modern humans) first evolved from a different humanoid species that looked more like monkeys residing in Africa, having lost the extra fur due to the continent's hot climate. During the Upper Paleolithic (about 40,000 years ago), the homo sapiens migrated from Africa to other continents, where they first interacted with the primitive Neanderthals (fun fact: ancient homo sapiens of this period supposedly had very sophisticated speech and were just about as advanced as we are today, bar modern technology). Homo sapiens didn't need nearly as much food as Neanderthals did, since their bodies were smaller and leaner. The Neanderthals all died out due to dwindling food sources, since they were hunting so much. Meanwhile, the homo sapiens survived due to their broader pallet that allowed them to eat not just meat, but also berries, fruit, vegetables, dairy, and grains for similar nutritional value, during the first (I think) ice age.
With that said, it's safe to assume that there wouldn't be any Neanderthals running around when Tarzan takes place (which I would guess is in the 1800s, during the Victorian era [1837-1901] based on the lady's [I forget her name] outfit). Being raised by a different species wouldn't cause Tarzan to literally devolve (the opposite of evolve), as the traits of homo sapiens are literally hardwired into his genetic code since his parents were homo sapiens as well. My question is, why does it look like Tarzan devolved when all he did was hang out with the monkeys?
Again, as a Christian, I don't believe in any of this. I know a lot about this because I've extensively studied evolution to be able to refute it in arguments, which is why I posed the question, simply because Tarzan more closely resembles Neanderthal man than homo sapiens.