Care to throw your baby in the water to prove it?
That's just what we did with both our babies when they were but two months old. They held there breath, up to about 30 seconds, and while they could not lift their heads above water to breath, they made effective swimming motions and swam to us. Most amazing, they thought this was all fabulous fun. There was at that time a public recreation program called 'Water Baby' that promoted this type of training. They are now both excellent swimmers and love being in the water and have raised their children the same way with the same results. It would be interesting to know if any other primate infants would react the same way to being introduced to the water.