I like the idea of the Aquatic Ape. It is not a mainstream one and unpopular with experts in human evolution, on the fringe, unproven and unresearched.
It goes something like this. Our ancestors lived on the shores of warm seas, around 6 to 2 million years ago. They spent long amounts of time in the water. They learnt to walk on two feet as they waded through water, supported until they got their strength and balance. Their brains grew larger as they ate shell fish which could provide enough vitamins and minerals to allow for expansion. Humans are mostly hair less and smooth skinned, like dolphins and other sea mammals; other smooth skinned creatures such as elephants are proven to have evolved from aquatic animals. We are streamline, have hooded noses, insulating fat and we can hold our breath, all useful for an aquatic life.
If I were to try to empathise with these ancestors, I would prefer the seaside lifestyle to the tough animal hunting existence on the Savannah. Maybe that is the appeal of the theory.
Link to BBC radio programme >>