For a good overview look at:
French, AR. Selection of High Temperatures for Hibernation by the
Pocket Mouse, Perognathus Longimembris: Ecological Advantages and
Energetic Consequences. Ecology: Vol. 57:185?191.
The paper basically says that for the pocket mouse it is beneficial to
remain euthermic primarily to avoid the metabolic cost of arousal from
torpor. I assume it muct also be of survival benefit in a pocket
mouse to be able to wake up and be up to speed quickly to reduce
predation risk.
I'd say that maybe bats are on the other side of the fence (though
we're not talking about hibernation here I realize). In college i did
a bit of bat tagging in caves in southern illinois. You could pick
the sleeping bats right off the cave walls/ceiling and because they
were in deep torpor they could not put up much of a fight. They's
wake up a little and scream at you, but then they's kind of curl up in
your hands and try to get up to speed/temperature to effect an escape.
Of course, we'd be able to tag them (via toe clipping) and put them
back up on the ceiling in a couple minutes, well before they got their
temperature back up.
My armchair ecological reasoning on the possible difference (I'm not
up on the literature)is that the bats in a colony safe in on a cave
ceiling may not have much need for a rapid escape response (unless the
bio students show up!), and so it is more energetically efficient to
opt for torpor over euthermia.
Does any of that make sense? |
