There are not many among us who can outrun a charging elephant, let alone an angry wart hog. But the main problem for humans living on a savanna is that we are spendthrifts when it comes to water. Humans have very dilute urine, wet dung, and we sweat more than any other animal. These, to some, do not seem like the hallmarks of a successful savanna native, at least until that big ol' brain kicks in. These scientists point out that, as apes go, we are remarkably well equipped for life in the water.
Humans can be surprisingly good divers.
Some Pacific island fisherman and Korean pearl divers dive routinely down 60-80 feet and stay submerged for three minutes. This may not seem that impressive to a seal, but it is far and away the record for a primate. Furthermore, humans have a strong diving reflex. As soon as our heads go under water, our heart rate slows, peripheral blood vessels contract, and most blood flow is shunted to the brain. Even more telling, say some, is the fact that human babies are born knowing how to swim.