Deer, foxes, rabbits, etc. are all warm blooded mammals that regularly experience sub-freezing temperatures that would kill humans in a matter of hours. How do they survive?
In: 1817
A lot of methods, sometimes in combination.
Some flock together to share body heat. For reference I’ve seen on documentary that a flock of penguins in the Antarctic can reach up to 45 degrees C in the middle just by being close to each other, the middle guys start boiling alive and the flock has to constantly shift so the freezing outer guys get some heat and the boiling inner guys cool off at the edge, it’s a brilliant tactic for social animals. (I had guinea pigs and they do this, it’s always surprising how hot it gets)
Larger animals lose heat far slower than small animals so can usually survive without having to flock, but they do seek shelter from wind and rain/snow which would accelerate the loss of heat – natural caves, mounds, thick brush can all do the trick.
Smaller, solitary animals dig burrows or find natural shelter, very often solid ground or a pile of leaves can be surprisingly insulating and the temperature underground is more tolerable than surface temp, and snow is also very insulating depending on the air content (think igloos) so a snowy ground wouldnt be that bad for anything under the soil. Foxes and kitties tend to curl up into a ball and use their tail as insulation for their tucked-in extremities.
Some animals hibernate because they’re just too small to retain their body heat and can’t find enough food to keep their internal fire going. Big animals can hibernate too, mostly from lack of winter food, though heat usually isn’t an issue.
Some animals specifically shed a light summer coat for a thick winter coat of fur when the weather turns cold, and the nature of fur keeps their skin warm and dry, even if the fur is tipped with snow/ice. (Furred animals have a very soft downy layer by their skin which traps heat, and a coarser outer layer to catch precipitation and keep the downy layer dry – if the downy layer gets wet it is rendered useless and actually draws heat from the animal even faster, an animal falling into an icy body of water has very little chance)
Having enough body fat going into the cold season makes a huge difference for any warm blooded animal, for both insulation and metabolic fuel. Preparing by eating excess when it’s warm is common. If food is not an issue in winter, the animals simply eat more and move more, they shiver and expend energy to generate more heat. (All warm blooded animals shiver but the ones that stay fed don’t deplete their fuel). Squirrels are a good example of an animal that ensures it has winter food.
Let’s not forget a lot of birds and rodents have adapted to live in human housing, and as we make sure to keep ourselves warm, the animals take advantage of the readily available warm shelter. Insects can also do this to avoid the frost which usually does kill them as they’re not warm blooded.
I know it’s not a mammal, but there’s a frog that can technically be completely frozen by frost, but will survive when thawed. I can’t remember what species but some animals produce a natural antifreeze in their blood that lowers the freezing point in their body, so fluids can still circulate even if the body is directly in contact with icy conditions.
Some birds and mammals migrate to somewhere warmer, simple solution.
It’s wild how so many animals have so many methods for avoiding freezing to death but as it’s a life and death thing, adaptations are sure to emerge.
Despite everything, sometimes it’s just not enough and a lot of animals do perish from the cold.
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