Re: Becoming altricial/bipedal

Lisbeth Andersson (
3 Oct 1995 19:19:38 GMT

In article <>, Paul Crowley <> writes:

>The immediate disadvantages of becoming altricial would appear to be
>catastrophic. The hominid mother, while foraging, must either awkwardly
>hold the infant or put it on the ground. If a predator approaches, she
>must locate it, pick it up and carry it in her arms while trying to run
>or climb a tree. On the other hand, the maternal chimp with her baby
>clinging to her can instantly flee and has unimpeded use of all her limbs
>for running, climbing as well as for foraging.

Or as an alternative: The earyl hominid baby's development was not
noticeably different from the development of the baby of the
common ancestor, which made it possible for the early hominid mother
to place it on her shoulders, where it could *sit* and cling to the
mothers hair.

Being bipedal also brings with it this new method of carrying children.
For newborn babies today, it does not work. If it worked for the
earliest hominid, depends on wether the child development resembled
the common ancestor or modern humans (or some stage between them).

This speculation also explains why we have hair on our heads.

>This amazing change had one cause: the development of the bipedal foot.

This is the first time I hear that foot development instead of brain
deveolopment should cause a long infant stage. All previous sources
I've seen claims that the helpless infant stage is linked to brain
development. And since the brain of the earliest found hominids
seems to be very similar to chimp brains, I see no reason to
assume that our first bipedal ancestor were altricial.

[lot of stuff deleted]


(The SIG works OK, now I have to think of something funny,
intelligent and characteristic to put here .....sigh.)

Lisbeth Andersson, Sweden