What is at issue here is the relative amount of energy & time of dependency upon parenting before the new born reaches maturity and is able to fend for itself within the species troop. Homonid sapiens take a much longer time to mature than apes.
But if you wish to see what I mean please see the following article: Evolutionary Context of Human Development: the Cooperative Breeding Model by S. Hrdy http://www.citrona.com/02Hrdy.pdf
On 6/6/06, Per I. Mathisen <per at fix.no> wrote:
> On Tue, 6 Jun 2006, Jerry Monaco wrote:
> > For instance most (possibly all) vertebrate species that take a
> > relatively long-time from birth to maturation seem to show certain
> > similar characteristics. One of those characteristics is cooperation
> > in raising children. Many sociobiologists propose that there is a
> > relationship between the length of maturation and cooperative
> > parenting. If there is no cooperative parenting then of necessity the
> > length of time from birth to maturity will be short. If the length of
> > time between birth and maturity is long-enough to tax the energy or
> > threaten the survival of mother and infant then there must be
> > cooperative parenting. It is true of all other species.
>
> Really? In all higher-level species, reproduction takes time and comes at
> significant cost and risk, but they do not all cooperate raising the
> young. Eg rats may cooperate, but cheetah and leopards do not. So I do not
> see the clear connection between the two. I would rather think there are
> many other variables in play.
>
> - Per
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>
-- Jerry Monaco's Philosophy, Politics, Culture Weblog is Shandean Postscripts to Politics, Philosophy, and Culture http://monacojerry.livejournal.com/
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