Comments on: Dolphin detects electric fields with ex-whisker pits

By: amphiox

amphiox — Wed, 27 Jul 2011 21:09:54 +0000

If there’s been enough time, things go when not used.

Perhaps. But that still means that we should be able to observe functionless vestigial features in modern organisms – features that had function relatively recently and have not yet entirely been removed.

By: Brian Schmidt

Brian Schmidt — Wed, 27 Jul 2011 18:01:02 +0000

“It is striking that bottlenose dolphins have been observed digging for food in the ground, where electroreception would be most useful.”

I wonder if there’s any relation to the use of sponges. Maybe the sponges increase conductive connection to the ground.

By: Scotty D.

Scotty D. — Wed, 27 Jul 2011 17:59:05 +0000

@Chris, if you re-read the paragraph, I think you’ll see that it isn’t pits or crypts that waste away, its the whiskers, which leave behind the pits called crypts. In other words, the crypts and the craters are the same thing. So I would imagine that all Guiana Dolphins have this sense. Although, I suppose its possible that the whiskers of newborns could impede this ability. But the whiskers probably waste away before the young dolphins need to use it to hunt anyways.

By: Chris Lindsay

Chris Lindsay — Wed, 27 Jul 2011 15:17:32 +0000

You wrote in the first paragraph “When dolphins are born, these pits house whiskers that soon waste away to leave empty craters.”

How long do dolphins have the crypts and utilize them before they’ve wasted away? And are there any behavior changes in the older dolphins that only have the craters?

By: Andrew Wilson

Andrew Wilson — Wed, 27 Jul 2011 07:13:32 +0000

Very cool. I wonder how (mechanical) whisker receptors get repurposed for electrical detection.

More evidence too, that ‘vestigial’ doesn’t mean ‘not being used for something else now’. Evolution actually is good enough to entirely get rid of things that aren’t being actively maintained; I like the fact that we still have an appendix, not because it fell below evolution’s threshold but because that’s the size evolution will support given it’s actual function. If there’s been enough time, things go when not used.