Yours is a complicated question because it covers some 80 species of
Cetaceans which range in nominal life spans from around 15 years (some
porpoises) to over 200 years (bowhead whale).
Your question's implied complication is double when one considers the
sex involved . . . male or female? In some species, the males are not
constrained by competition for females . . . they just go for it as
soon as they can (less than eight years of age). In others, dominant
males battle other challengers for the opportunity to mate. In this
case, a breeding male is not likely to have a successful engagement
until a later age once they are bigger and stronger to fight for the
females (older than 12 years old).
In some whales the female's reproduction years might last from age four
to fifteen and they can become pregnant every year. In others, the
female's breeding period might be six to thirty five, buy they may
carry a calf only every third year. In another species, the female's
first breeding might come later, say ten years old, and produce a calf
only every fifth year.
Another factor is the condition of the species and the environment. If
a species is greatly reduced by whaling or other impact, reproduction
tends to accelerate. If the environment is out of whack, say in an El
Niņo year, they may put off mating until there enough proper food
readily available.
So, it is very difficult to come to an 'average' because of all the
variables. It is easier to determine an average if one specifies which
species.
Cheers,
Pieter Folkens
On Nov 2, 2003, at 12:57 PM, SpAzEt619@aol.com wrote:
> Dear Pieter Folkens,
>
> On average how many times does a whale reproduce during its
> lifetime?
>
> Amy Bessette
>
This archive was generated by hypermail 2b30 : Wed Nov 05 2003 - 17:54:39 EST