I have a planet where the equator temperatures are near boiling point (90˚C or 194˚F) during the "summer". What qualities would an animal need in order to survive these kinds of temperatures to conserve water? A couple things to qualify:

  1. The animal is slightly larger than a coyote.
  2. It is naturally nocturnal and only moves outside at night, where the temperature is closer to 65 C (150 F).
  3. The animal must find and use liquid water for hydration, no pulling water vapor out of the atmosphere.
  4. Assume there are some plants much like cacti, and one could harvest water from it.
  • $\begingroup$ I've read a couple of papers that suggest the upper theoretical limit of thermal survive-ability for life is around 122 deg. Celsius. Personally, I think complex life forms (even cacti) are going to struggle to survive such temperatures, water or no. Warm blooded creatures need an upper differential over the long term to survive, and cold blooded creatures would have to eat like crazy to survive their metabolism boost by these sorts of temperatures. Either way, your animal fares better with cooler subterranean caverns and the like to wait out the heat. $\endgroup$ – Tim B II Dec 18 '17 at 1:40
  • $\begingroup$ How dry is the climate? I would think a creature adapted for 90 degrees in a humid place would just feel normal $\endgroup$ – Andrey Dec 18 '17 at 2:04
  • $\begingroup$ @Andrey I am asking for what adaptions it would need to survive. $\endgroup$ – OneSurvivor Dec 18 '17 at 2:09
  • $\begingroup$ @TimB 122° Celsius is above the boiling point. I think you mean 122° Fahrenheit. $\endgroup$ – B.fox Dec 18 '17 at 2:24
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    $\begingroup$ Hmm, yeah. Complex life would certainly not stand. A life form like that would need to shed a lot of heat somehow, and would need to have a decent external insulator for vitals. I'm thinking of an animal that breathes heavily and a lot to remove inner heat, has a thick and dry outer skin as an external insulator, and has a powerful circulatory system (or even a separate one specifically for moving heat away from vitals). In short, a living refrigerator. $\endgroup$ – B.fox Dec 18 '17 at 2:36

No offense, but you must not barbecue much

Steak is cooked rare at about 130 F. This means that the proteins in the meat have started to denature, losing their higher level structure. At 150 F (as any good BBQ-ist knows) fat starts to render...to melt. By 160 F, white meats are cooked through, steak is well done, and pretty much any bacteria (hi Salmonella) is neutralized.

The result of this heat is that no living organism can survive. The denaturing of the proteins is the key: if you want to have complex amino acids driving all sorts of complex internal systems, then you can't have your proteins changing shape and such. Having the lipids in your stored energy reserves melting isn't going to make things any better.

The conclusion here is that no creature can keep an internal temperature this high.

Is it reasonable for a creature to cool itself?

Lets say that you need your body temp at 120 F maximum to keep complex proteins intact (I don't know if that is reasonable or not). Is it reasonable for a creature to cool itself against those kinds of conditions?

Well, based on the life experience on Earth, the answer is no. Thermo-regulating mammals are able to control their body temperatures in the range of 95-110 F. The hottest place I can find on Earth is Ahvaz, Iran; with an average daily temp of 99 F in July. Basically, there is no record on Earth of a thermo-regulating animal living in a place where the average temperature is higher than its body temperature.

Extrapolating from that; if the cold conditions are 150 F and 150 F is going to cook your creature, then you cannot have advanced life forms live there.


Your creature must not have Earth's carbon-protein-fat based biochemistry.

Of course, once you do that, suggestions on what sort of chemistry and metablic processes to use could be endless. They are definitely a 'too broad' kind of question. So lets just leave it that Earth's biochemistry won't support an advanced creature living in those temperatures.

Note to haters: I'm specifically ignoring Pompeii worms and tardigrades and such that do survive at extreme temperatures, since they don't seem to bridge the gap to the OP's 'coyote-like' creature.

  • $\begingroup$ I think you should add also archaebacteria to the list of ignored living organisms. $\endgroup$ – NofP Dec 19 '17 at 22:04

Kingledion already pointed out that most complex life form definitively cannot survive in an environment with permanent temperatures above 50C (120F).

Most animals would probably migrate away from that region but to answer your question, let say that this region is an island. Most animals would probably dig a very deep hole and burrow underground and wait the summer to pass.

It would be very akin to hibernation, just the opposite way.

The animal would probably be very fatty, and have huge paws excelling at digging holes.

It would also have some sort of way to slow down it s metabolism.

It could also just become amphibian and dive deep in water. 20m below surface should be cool enough for the animal to survive.

It might even not need to be amphibian, it could just be able to stay for extendend period under water, only periodically needing to resurface to quickly breate and then dive back (like dolphins, whales and penguins). For short periods of time 90C could be bearable if your body is in the water and you just stick your nose out to breathe (think of saunas).

  1. Many desert animals get the water they need from their food; the kangaroo rat is an example. Oxidation of reduced carbon (like sugar or fat) produces water as a byproduct. If your body is good enough at reclaiming the water you can excrete crystals instead of liquid urine and get the water you need from your food.

  2. One of the other answers noted that proteins denature at heat. There are organisms who live at temperatures higher than what you propose, who do not get denatured or broken down by the heat.

from http://www.genomenewsnetwork.org/articles/08_03/hottest.shtml

Scientists are also intrigued as to how strain 121 and other extremophiles can survive such harsh conditions. Most biological compounds such as DNA, proteins, and the lipids that form the cell’s outer membranes, are degraded at much lower temperatures. Lovley is studying the lipids in strain 121 to figure out how its membrane survives temperatures above the boiling point of water.

Alexei Slesarev, who studies high-temperature extremophiles at Fidelity Systems in Rockville, Maryland, says the key to their survival may be the unusually high concentrations of salt and ions inside the cells.

If your animal were some colonial form of archon like this, it might do ok in the heat.

  1. Endothermic reaction. This is pure science fiction now and I do not know of any creature that does this. Certain chemical reactions are endothermic - they consume heat - and among these are the "cracking" of long chain alkanes. When done industrially this requires high temperature and pressures. This is also true for industrial fixation of atmospheric N2 gas into forms useable as fertilizer. But nitrogen fixing organisms accomplish this enzymatically in the cool earth. Maybe your creature can enzymatically crack long chain alkanes and cool itself with the endothermic reaction?

One would need a supply of long chain alkanes - a tar seep would do. If you are going to have this sort of exotic biology you could have the organism use the cracked alkanes as energy too - some organisms can do this (witness the organisms that gobble up oil spills). Unoxidized volatile short alkanes evaporating out of the creature will also cool it. Oxidizing alkanes will produce your water as well, as can be seen in the exhaust of a car on a cold day.

A creature living this lifestyle would not want to venture too far from its tar seep, unless it was seeking a mate.


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