I have found numerous questions on how cold blooded humanoids or at least an intelligent species could survive the cold on this site, but this is not the question I am asking.

I want to know specifically how an animal, a being with very limited intelligence would survive perpetual cold. Furthermore, I know of fish and other types of critters like worms or starfish that can survive arctic oceans, but I am more interested on how a cold blooded being would survive on land. Let us assume temperatures below freezing point, or just slightly above it if that makes it more possible.

As far as I know we have cold blooded creatures on earth that can survive a winter, but none that can thrive in perpetual cold. If I am not mistaken on the poles, for example, only mammals and birds are found on land, but no reptiles, amphibians, insects or worms.

  • $\begingroup$ Do frogs count? $\endgroup$
    – Zeiss Ikon
    Commented Nov 30, 2022 at 16:44
  • $\begingroup$ Well you mentioned that you've heard of cold blooded animals that can survive in the arctic ocean. Take a page out of their book and have a look at some of the unique adaptations of the antarctic icefish! For example, they have no hemoglobin, they simply dissolve oxygen directly into their blood and transport it that way. You might also want to consider how they'll stay warm enough to do normal animal things. Direct sun can heat objects above the ambient temperature, depending on the type of surface: maybe your animal is very black and absorbs a lot of heat from the sun. $\endgroup$ Commented Nov 30, 2022 at 16:49
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    $\begingroup$ There are insects in Antarctica. smithsonianmag.com/smart-news/… $\endgroup$
    – Boba Fit
    Commented Nov 30, 2022 at 17:09
  • $\begingroup$ Keeping in mind that per the help center our job is to help you build an imaginary world, what is your specific question? Are you seeking help rationalizing (e.g.) animal life on something like Star Trek's Delta Vega? We're pretty good at creature-design, but if you're looking for godlike insight into the creation of an actual animal that can do that... we come up a bit short on that. So, what's your specific expectation with this question? Because helping to design an entire biome violates the help center's book rule. $\endgroup$
    – JBH
    Commented Nov 30, 2022 at 17:17
  • $\begingroup$ Small bugs can be seen out and about on the snow in the winter when it's not very cold, say, above minus five degrees C. They have chemicals in their tissues that work like antifreeze. Some, like snow flies, can even reproduce in the winter. $\endgroup$
    – Cloudberry
    Commented Nov 30, 2022 at 19:34

1 Answer 1


Regional endothermy.

Some cold blooded fish produce heat on demand via muscular action. Recycling (part of) my other answer!

Is there any plausible in-between of Endotherms and Ectotherms?

http://bioweb.ie/warm-blood-sharks-tunas-superspeed/ enter image description here

Regional endothermy as a trigger for gigantism in some extinct macropredatory sharks

Regional endothermy is the ability of some fish lineages to maintain certain body areas at higher temperatures than the surrounding water by means of vascular countercurrent heat exchangers or specialized thermogenic organs. This adaptation involves an active mode of life and much higher metabolic rates than those of the ectothermic fishes of the same size... Here it is proposed that regional endothermy was present in otodontids and some close related taxa (cretoxyrhinids), playing a key role in their evolutionary history, allowing gigantism and the maintenance of active macropredatory modes of life.

So with your land creature. It would lie around and be cold if there was not much to do. Maybe even freeze. That is definitely more economical than the warm blooded animal plan of staying hot all the time. If your critter needed to do something - hunting, looking for a mate, gestating young, dancing the forbidden dance - it would use muscles to warm up relevant body parts.

Insects are a fine example of a cold blooded land animal that can generate heat on demand via muscular activity.

Thermoregulation in insects

An endotherm is an animal that produces metabolic heat specifically for thermoregulation. Endotherms have been identified in many insect orders. The source of heat in endothermic insects is the flight musculature. Endothermic insects will increase heat generation through muscular activity to elevate body temperature to the range necessary for activity. The heating can occur without flight or wing movements but shivering can be observed in many night flying moths or bees at flowers on cool days prior to take-off.


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