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Re: What is an "active ectotherm"?

First, endothermic means nothing more or less than that the majority of body
heat is produced internally. Because the oxygen consumption and burning in an
animal with high aerobic capacity will tend to be high, most body heat will
be generated internally. It will therefore be an endotherm. Whether it will
regulate its body temp as tightly as a bird or mammal is another matter, but
it is not reptilian nor ectothermic.

Second, it is probable that certain complex limitations of the centralized
vertebrate respiro-circulatory system force all those examples with high
aerobic capacity to have a high resting metabolic rate as well. This is the
basis of the aerobic capacity hypothesis, which argues that all animals with
high aerobic capacity have a high resting MR because they have to whether
they like it or not. Some speculate that vertebrates can have high AC and low
RMR like insects (which have a decentralized oxygen delivery system), but
this hard to test as well as highly speculative.