Re: possible role of echolocation in K-T survival

[Betty Cunningham <bettyc@flyinggoat.com>]

> >isn't echolocating similar in principle to sonar?  The medium is
> >different, and the reception of sound is through different body parts
> >(ears vs. melon), but isn't the principle of issuing sound to recieve
> >sound wave bounces the same?
> >
> >Could ichthyosaurs have used sonar?
> 
> Possible - except that many ichthyosaurs had enormous eyes, if the size of
> the orbits is any indication.  Most living echolocators tend not to
> emphasize visual integration.

Sperm whales have the largest extant eyes I know of, and they use
sonar.  Not quite the proportions of an Ichthyosaur however. 
Would something like a melon be traceable in the fossil record?  Would
it be possible to have a non-mammalian melon?

-Betty Cunningham