Re: Endothermic Crocs in Nature

[Tim Williams <twilliams_alpha@hotmail.com>]

Jura <pristichampsus@yahoo.com> wrote:

> The results of automatic
> endothermy are NOT a high activity level and
> endurance, both of these have been shown to be
> independent of automatic endothermy (see mako sharks,
> tuna, bees, ants, and near any autarchoglossan lizard,
> for examples).

Lamnid sharks (makos, great white shark, porbeagles) have a system known as 
"regional endothermy".  Here's a summary:

http://www.ncf.carleton.ca/~bz050/wsphysio.html

> Larger animals do not have higher metabolic rates than
> smaller animals. They have LOWER metabolic rates. An
> elephant might eat a lot of food per day, but compared
> to body size, it is but a tiny fraction of the food
> consumed by a gerbil everyday. It's amazing how much
> energy can be saved when one isn't just burning up
> everything to keep warm.

I have to agree with you here.  The high surface area to volume ratios of 
small mammals (and birds) means they have to eat much more per unit body 
weight than a larger-bodied terrestrial endotherm.  In general, anyway.


Tim