MORE ON HETEROCEPHALUS

["D.W.Naish" <dwn194@soton.ac.uk>]

> I THINK naked mole rats are ENDOtherms that have replaced body 
> insulation with total burrow existence.

I THINK naked mole rats are ECTOtherms that have.. hang on, all other mole rats
live in burrows, yet are furry, as are moles, marmots, ground squirrels and so
on. Naked mole rats are aberrant: they are matriarchal with only one breeding
'queen' in a colony (she actually puts out hormones into the colonies'
collective dung pit that inhibits breeding in the other females). They live in
tight-nit communities of (mostly) blood relatives and work, as do social
insects, in a way we typically regard as altruistic. Why they lost their fur I
don't know, perhaps naked skin was a better idea in tight tunnels (their skin
is very baggy and loose). An endothermic physiology was perhaps found
unnecessary in the climate, lifestyle and habitat they have adapted to.

> I think.  When we were in Africa, we held some of these (in my opinion) 
> revolting little animals.  They seemed very warm.   
> JCMcL

I have held lots of 'cold-blooded' lizards and snakes that are very warm to the
touch. Means nothing physiologically.

Regarding endothermy in fishes, scombroids (tunny, sailfish, swordfish etc)
generate heat in their eyes and myotomes to aid performance. Great white sharks
distribute the heat created by digestion throughout their bodies, and I guess
lots of other 'ectotherms' do too. But at least some fish really can generate
their own internal heat.

"Those daleks next door open fetes and things all the time"

DARREN NAISH