Re: Whale embryos: do whales ever develop legs?

From: monahan_d@hccanet.org
Date: Mon Apr 23 2001 - 09:21:10 EDT


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



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