If my 2 year old's table manners are any evidence, "throwing things" starts pretty early too. "like birds fly," may be a bit of a stretch, unless you're Justin Verlander, but still I appreciate the thought. While the ability to throw as accurately as humans can and with the velocity and distance that we can is unique to us, there are some primates that give it a pretty good go. Consider Santino, a male chimp in Sweden that will hide rocks under piles of hay in a plot to later hurl them at visitors. But we definitely have the advantage in the throwing department over our ape friends, though it seems that there is a bigger disparity in accuracy between male/females in humans than in apes. I wonder why that is and what selected for that? theadvancedapes, was this a result of men being the "hunters" and therefore having to be more accurate with a spear?
Research on chimpanzees (the only other adept throwers in the animal kingdom) has shown that communication capability is tightly correlated with throwing ability. Primatologists also found that throwing ability was tied to a well developed area of the left hemisphere called Broca's area. This area of the brain is responsible for speech in humans. Therefore, some have suggested that accurate throwing may have been a form of communicative self-expression (i.e., I don't like you and I'm going to let you know about it by pelting you with rocks). I'm not so sure myself. I'd have to do some more research. And in terms of the difference between men and women - that would seem to support a hypothesis related to hunting. However, it is important to note that hunting with long-distance projectiles (e.g., spears) is a modern human development; no other Homo species I know of developed that technology or ability.
It most certainly could be. The reason I was slightly reserved with my analysis is because there seems to be competing hypotheses in the literature and I have only read the primatology literature on chimpanzee throwing. However, I have not read the paleoanthropological literature which may support the hunting hypothesis. Maybe EvoAnth can help!