From: Sandy Petersen (sandyp@idgecko.idsoftware.com)
Date: Fri 08 Mar 1996 - 09:27:58 EET
Mark Groff
>The whole idea that trolls would be cold blooded is absurd. It is
absurd for >any sentient creature living in a temperate or colder
climate. The primary >advantage that cold bloodedness brings to a
creature is a low baseline >metabolic rate, thus a cold blooded
creature only needs to eat about a tenth as >much as a same sized
warm blooded creature (does this sound like any troll that >you
know?).
This isn't really so,l as I will soon explain. Note that I
don't think that cold-blooded/warm-blooded has meaning in Glorantha
anyway, especially with regard to trolls. BUT, as a stickler for
biological accuracy, I step in.
>The disadvantages are; 1) that it means that their level of
activity is largely >dictated by climatic events, when it gets cold
they go into torpor
So do warm-blooded creatures, who are direly affected by
cold. The great majority of warm-blooded animals who live in cold
climates are forced either to migrate or to hibernate in cold
weather.
>2) cold blooded creatures while generaly capable of great bursts
of physical >activity they have almost no staying power because
their activity relies almost
>entirely on anaerobic metabolism.
This depends on the animal, not on its bloodedness. All
oxygen-breathing animals have access to both anaerobic and aerobic
metabolism in varying degrees.
>For a sentient creature to be both cold blooded and live in a
temperate or cold >climate would be a disaster. Many nights and all
winter they would spend in a >hibernatory torpor, complete sitting
ducks for all those who have trolls on >their better off dead lists.
Yes, far better to be warm-blooded like a raccoon or a bear
and thus sleep in insensate coma for the months of winter.
The advantage to warm-bloodedness is that you have more time to do
things, and that your metabolism normally is more finely tuned. The
cost is, as Mark says, a much faster metabolism during active times.
1) More Time To Do Stuff: "Cold-blooded" animals actually
maintain a pretty constant temperature during the day. This is done
by behavior. A lizard creeps out of its lair at dawn, basks on the
darkest, sunniest stone available until it heats up (usually to
quite a few degrees warmer than the surrounding air). Then it is
active until it begins to overheat, when it tucks itself into the
shade for a while, etc. A cold-blooded animal must spend a fraction
of its day doing this kind of maintainance, whereas a warm-blooded
creature has its metabolism kept stable automatically, though
extreme heat and cold are still reacted to behaviorally.
2) More Finely Tuned: even though you can maintain a
constant temperature during the day, it's not all _that_ constant,
and has its ups and downs. Your body's various enzymes and processes
have to be designed to work within a reasonably wide range of
temperatures. A mammal's enzymes don't -- or if the mammal
hibernates, most of its processes simply shut down, rather than work
at two different temperatures. Hence a mammal's enzymes and biology
are generally more finely-designed than a reptile's.
That said, this only counts if the animal lives in a place
with the temperature constantly changing. Fish have a fairly stable
temperature, and thus can stay active all the time. Dinosaurs were
so large that they could retain a constant body temperature all
night long (in fact, their main problem was probably _dispelling_
heat, rather than generating it).
Sandy P.
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