Subject: Monogamy in whales?

Phil Clapham (
Thu, 07 Jan 1999 13:21:56 -0500

Hi Maria:

Great question, thanks.  Actually, you may be disappointed to learn that
- all myth to the contrary notwithstanding - whales don't practise
monogamy.  True monogamy is in fact extremely rare in any mammal (some
people would say that includes humans!)  It is widely cited as common
among birds, but recent paternity analysis using genetics has
demonstrated that many species of birds thought to be monogamous are in
fact not.

Among whales, mating systems vary but most are generally considered
polygynous (one male mating with more than one female, in various forms)
or promiscuous (both sexes may have more than one mate).  For a long
time, people thought that large whales practised monogamy because of
some anecdotal observations.  For example, humpback whale mother/calf
pairs on the breeding grounds are frequently accompanied by an escort
whale who is invariably male.  Ity was assumed by whalers that this had
to be either the father of the calf, or perhaps an "aunt".  Genetic
analysis has shown that in the great majority of cases, the escort is
unrelated to the calf, and is likely hanging out with the mother in the
hope that she comes into oestrus (and may therefore be a potential
mating partner).

Phil Clapham

P.S. I discuss this issue in a bit more detail in my book "Whales of the
World" (published last year by Voyageur Press)

> Maria Moher wrote:
> Hi,
> I was wondering if you can tell me if the whales are the only mammals
> that practice monogamy.
> Can you give me as much information on this issue.
> Thank-You
> Maria


Phillip J. Clapham, Ph.D.
Northeast Fisheries Science Center
166 Water Street
Woods Hole, MA 02543

tel (508) 495-2316
fax (508) 495-2066