We have found extremophiles of the aquatic and microscopic types here on Earth, but so far large terrestrial extremophiles are the stuff of conjecture only. This makes it somewhat challenging to speculate whether terrestrial creatures could survive on a moon heated by tidal forces of a large nearby planet/geo-thermal heat.
I'm trying to envision a realistic scenario in which cold-blooded creatures (more precisely known as ectotherms) inhabit a moon orbiting a planet far from the habitable zone. Here is what we are working with:
- Assume the moon has everything needed to support life as we know it (magnetic field, breathable atmosphere, geo-thermal heat, ect)
- Assume the ectotherm to be a very large lizard, say a komodo dragon
We might feel inclined to clap our hands together and say 'voila! we're done!' However, further analysis leaves us apprehensive about a large terrestrial ectotherm surviving on a such a moon solely on geo-thermal heat. A moon heated via tidal forces from a its parent planet will presumably be very geologically active. One second our lizard-like ectotherm is enjoying a nice soak in a hot spring, then BOOM: he's consumed by a pyroclastic flow from one of the many volcanic eruptions.
Given that tidal force warmed moons can be overly dangerous (take Io for instance), is there a more, shall we say, "peaceful" way of allowing for the survival of large terrestrial ectotherms on a moon outside of the habitable zone? If I must resort to large tidal forces inducing geo-thermal heat for ectotherms on this moon, then how will the large ectotherms cope with the geologic upheaval that comes with such a world?