[Endymion]

Is there a reason for the male attraction to breasts? Someone suggested that shortly after the species 'learned' to walk upright, the female sex (now with it's genitalia not easily visible from behind) developed larger breasts to be an openly visible prompt to their sexuality (to mimick their posteriors). This is not the case with other primates, where female breasts only swell marginally for lactation.

Also it's quite likely there was a water stage in our evolution, similar to that of a seal. Evidence of this is our webbed thumb and our streamlined hairs, also not found on other primates.

There's a book called The Human Animal that explains this better.