[Taxacom] Eccrine glands

[Kenneth Kinman]

Hi Curtis,
      Well, I didn't actually set myself up, because I specified "fish".
Owls are descendants of fish, but they are not fish.  And that's why I
didn't say Sarcopterygii, because the hijacking of that term has
inevitably led to confusion.                    
      As for eccrine glands, one could probably write a whole book on
their distribution.  In short, different mammalian taxa solve their
thermoregulatory problems in different ways.  Carnivores pant (think of
it as "internal sweating" through the lungs) probably because
sweat-soaked coats would be problematic.  People and horses with less
dense coats can more freely sweat externally.  Elephants could have done
the same, but they conserve water by using their big ears to
thermoregulate.  Also depends on the availability of water to drink and
in their food (desert animals can't afford to sweat a lot).      
            ----------Ken                        
        
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Curtis Clark wrote:
On 2009-03-23 08:09, Kenneth Kinman wrote: 
> (1) Are there any fish (either actinopterygian or >sarcopterygian)
that 
> also have nictitating membranes?    
Yes. In the Sarcopterygii, owls. 
(Sorry, Ken, but you set yourself up for that one. 
I do want to say that I value your attention to these features, and I'd
be interested in your take on the presence/absence of eccrine glands on
most body surfaces of mammals. Dogs have eccrine glands more or less
restricted to the feet, iirc, but humans and horses have them over the
entire body surface.)