Perhaps, but as far as I know no other primates (not merely apes)
display the whole range of adaptations (voluntary breath control,
metabolic dive reflex, downward-turned nostrils, streamlined hair
patterns, neonatal swimming ability, extensive subcutaneous fat,
all of which are of unquestionable advantage to a wading/diving
lakeshore animal). Add in the several other unique traits of Homo
sapiens that may have been of advantage in an aquatic environment,
such as bipedalism, semihairless skin, and possibly modified coital
position, and Ockham's razor starts cutting into your suggestion
rather deeply.
Can you name one other primate, even a very "primitive" one,
that displays even three of these aquatic adaptations? It seems
unlikely that such a large array of distinct adaptations could
have developed as a group in some common ancestor of very many
species, and then be systematically eliminated from all of the
descendant species except one, which preserved so many. If one
species preserved so many aquatic adaptations, then it would
seem very unlikely for selective pressure to have wiped out the
whole suite of adaptations in the cousins without any vestigial
remainder. Vestigial remainders are fairly common in mammals
generally, so it seems that when evolution wipes out a trait, it
rarely does so without leaving a trace.
-- Eric Watt Forste ++ arkuat@pobox.com ++ expectation foils perception -pcd