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Endothermy
and ectothermy are usually considered mutually exclusive characteristics.
While endothermic animals (birds and mammals) can maintain internal body
temperatures by producing metabolic heat, ectothermic animals depend on
an external source of heat, thus their core temperature changes with that
of their surroundings (Schmidt-Nielson, 1998).
However, the temperate region bat proves an interesting exception in which
these two classifications seem to converge.
During the warmer part of the year, when insect supplies are abundant,
these bats maintain high well-regulated core temperatures, but when temperatures
begin to drop along with the food supply they are faced with a choice—migration
or hibernation (Wimsatt, 1970). Those
that undergo the latter, allowing their body temperature to drop to nearly
0ºC for part of the year, can be referred to as temperal heterotherms.
For these bats seasonal dormancy influences their entire life cycle, especially
reproduction, growth, development, and
fat storage—all which must take place during
their period of activity (Davis, 1970; Lewis,
1993; Schmidt-Nielson, 1998; Wimsatt, 1970). |
Thermobiology
