Whale embryos: do whales ever develop legs?

From: Erich Hoyt (e.hoyt@virginnet.co.uk)
Date: Mon Apr 23 2001 - 23:38:03 EDT

>From: monahan_d@hccanet.org
>To: Erich Hoyt <e.hoyt@virginnet.co.uk>, monahan_d@hccanet.org
>Subject: Re: Whale embryos: do whales ever develop legs?
>Date: Mon, Apr 23, 2001, 6:21 AM

> Dear Mr Hoyt,
> Thank you for your response. You provide a valuable service! As an
> update: I have not found any photos of whale embryos, but I found some
> diagrams in Mark Ridley's book EVOLUTION. Thanks again.
> Dan Monahan
> --On Sunday, April 15, 2001, 12:04 PM -0700 Erich Hoyt
> <e.hoyt@virginnet.co.uk> wrote:
>>> From: monahan_d@hccanet.org
>>> To: e.hoyt@virginnet.co.uk, pita@whale.wheelock.edu
>>> Subject: Whale embryos
>>> Date: Wed, Apr 11, 2001, 10:30 AM
>>> Dear Mr. Hoyt,
>>> I am a highschool biology teacher working on an evolution exhibit. It
>>> has come to my attention that at some stage in the development of whale
>>> embryos primitive hind legs are visible and then dissappear. Is this
>>> true? and can you tell me where to find a picture of this stage in a
>>> whales development? Thanks!
>>> Dan Monahan
>>> LaSalle High School
>>> 3901 North Bend Rd.
>>> Cincinnati Ohio 45237
>>> monahan_d@hccanet.org
>> Dear Mr. Monahan,
>> There is nothing about this in the fairly comprehensive Biology of Marine
>> Mammals, published by the Smithsonian Institution Press in 1999. And the
>> various other whale scientists I asked knew nothing about this.
>> However, a developmental biologist I know who works on mice and chickens,
>> says that there is almost certainly a stage in very early whale
>> development when there are limb buds present but they don't develop. Even
>> snakes have limb buds and the capacity to grow limbs. But it wouldn't be
>> a case of legs appearing and then disappearing.
>> The early developmental biology of whales is not something that is really
>> studied, at least at present. As you can imagine, the difficulties of
>> studying embryos at sea, much less the early developmental biology, are
>> problematic, and experimental research is clearly impossible, so
>> embryologists and developmental biologists choose easier more accessible
>> animals such as mice, chickens, etc. It is possible that there is some
>> data on this buried in whaling records, especially for those trips when
>> scientists were involved; but you would have to go back into records more
>> than 25 years ago, when whaling was still being carried on.
>> It might be worth consulting the following book which has a section on
>> evolution of cetacea (which I don't have handy at the moment or I would
>> check it) :
>> Gaskin, D.E. 1982. The Ecology of Whales and Dolphins
>> In addition, I might add that there are some fascinating cases of whales
>> being found with vestigial legs. A humpback whale landed on Vancouver
>> Island, Canada, in 1919 had 4 foot long (1.2 m) legs.
>> Unfortunately, I don't have or know of any photos showing legs or even
>> the leg buds of whales.
>> Good luck with your exhibit.
>> Sincerely,
>> Erich Hoyt

Dear Mr. Monahan,

Thanks for the useful feedback, and good luck again with your exhibit. Let
us know if you find out more, and I too will let you know.

With best regards,

Erich Hoyt

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