Comments on: Is Bleaching Next? Whales Look at Teeth When Picking Mates

By: Andy B

Andy B — Sat, 21 Feb 2009 20:26:13 +0000

You made some good points there. I did a search on the topic and found most people agree with your blog.

By: neil

neil — Wed, 31 Dec 2008 02:29:04 +0000

@ Erika – the function of narwhal tusks continues to be debated, a sensory function is likely, however tusks are strongly sexually dimorphic being generally absent or small in females.

By: Erika

Erika — Sat, 20 Dec 2008 00:48:14 +0000

I thought that a couple years ago scientists showed that the narwhal’s tusk was essentially an inside-out tooth, that they use for sensing temperature, pressure, etc. in their environment. I wasn’t aware that it was also a sexual characteristic.

Beaked whales are interesting critters- I didn’t know they were so unusual. Too bad we don’t have more information about them.

By: neil

neil — Thu, 18 Dec 2008 20:37:19 +0000

Sorry, I didn’t explain myself well.

The point I was trying to make is that dimorphism of secondary sexual traits is well documented in a variety of marine mammals, including those I listed. These differences arise (at least in part) through sexual selection and, by definition, shape the evolution of the animal in question. However, there have been many studies into the importance of sexual selection in the evolution of marine mammals and it seems unfair/misleading not to recognize this work.

The claim made by Dalebout et al. (2008) is subtly, but importantly, different. They state that this study documents the first known case of sexual selection driving evolutionary radiation (i.e. rampant speciation) in a “non-ungulate” mammal. I’ll leave it to those with the interest and access to Google Scholar to assess the validity of this statement.

At any rate, it’s a very interesting paper and I don’t mean to detract from it at all. I just thought it was worth mentioning that beaked whales don’t appear to be unique among marine mammals in this regard (although perhaps they are an extreme case at least among the living fauna).

By: Boonsri Dickinson

Boonsri Dickinson — Thu, 18 Dec 2008 18:39:17 +0000

Neil, the marine mammals are the beaked whales.

By: Rob

Rob — Thu, 18 Dec 2008 02:10:22 +0000

Is it a coincedence that there’s a teeth-whitening ad in the top bar as I’m looking at this article? Is this a wonderful product placement or somebody’s excellent idea for a joke? Either way, I’m very impressed.

By: neil

neil — Thu, 18 Dec 2008 02:04:58 +0000

a discovery that marks the first time scientists have found a secondary sexual characteristic (like antlers) that shaped evolution in a marine mammal.

Er, walrus? Elephant seal? Sea lion? Sperm whale? Narwhal? Humpback singing?