Winter Survival: Snow, Sleep, and Survival

Hibernation has always sounded so cozy to me. I think I could quite happily sleep months at a time. But in reality for many animal species it is a gamble. Without enough stored up fat, an animal might not make it through the season. This lead is a known fact but recently I have been wondering, how do animals minimise the risks of hibernation? It turns out that some hibernators take a different approach and here’s how…

🐻 Bears: Sleepy, But Not Asleep
Bears don’t hibernate in the traditional sense, which came as a surprise to me. Instead, they enter ‘torpor’, which is a state where their metabolism slows. In this state they can still wake up if needed, especially mother bears, who might have tiny cubs nestled beside them in the den. A struggle I think most non-bear mothers know all too well.

🦔 Hedgehogs: A Cosy Curl-Up
Hedgehogs take the classic approach. By curling into tight little balls, Hedgehogs actually slow down their heart rate and breathing. In this state they snooze for months at a time, surviving entirely on the fat they’ve built up. Though as impressive as that is I cant imagine myself not having to get up for a snack.

🐸 Frogs That Freeze
Now, this is where Amphibians really show off their stuff. During my little investigation into winter survive techniques, I found out something that blew my mind about North American Wood frogs. Turns out that they can literally freeze solid, Impressive right! The wood frog’s heart stops and their blood thickens. Sounds wild, but these clever creatures actually circulate large amounts of cryoprotectants (for example like glucose) through its body before it faces the freeze. This helps them to avoid any tissue damage before they thaw again in spring. Then its back to hopping on their merry way until next winter.

🐿️ Ground Squirrels: Almost Frozen, But Not Quite
Seeming to take a leaf out of the wood frogs play book, Arctic ground squirrels use a very similar technique to survive in freezing conditions. I found out that these clever little guys can lower their body temperature to just above freezing when they hibernate. In fact, their body temperature is the coldest of any mammal. To avoid their body temperature from dropping too low these north American ground squirrels will simply shake off the cold. They shiver periodically for roughly 12 to 15 hours! His increases their body heat back to the minimal temperature for survival. Though I think if I was that cold I would be shivering too!

🐒 A Lemur With a Fat-Tailed Secret
Here is one you probably don’t expect. Did you know that there is even a species of primate that hibernates in Madagascar. The Fat-tailed dwarf lemur hibernates for up to seven months in periods of torpor, surviving from the fat stored in its tail. During this time Fat-tailed lemurs heart rates drop to as low as 8 beats per minute!  Like bears, these primates not enter a true hibernation and will have interbout arousals occurring every 6 -12 days.

My research into animal winter survival strategies got me think, what happens to the animals that cant hibernate or migrate? It was something I hadn’t really thought about before, but typical for me I began to think about what interesting behaviours and adaptations animals might have developed to survive the cold. What I found out blew my mind.

❄️ Snowshoe Hares: Masters of Disguise
During my little reading session I came across something unique about the Snowshoe hare. Now I have heard of this species before but never really thought about in depth. During the winter months the Snowshoe hares coat turns white, which makes for perfect camouflage in the snow. However, this cleaver trick can be a disadvantage with our changing climate. Climate change has made snow fall unpredictable, leaving some hares snowy fur standing out against the bare ground.

🦊 Arctic Foxes: Fluffy Survivors
Did you know that arctic foxes have the warmest winter coats. Not only that, but under their dense fur they have a layer of fat keeping them nice and toast at temperatures of 40°F. If that isn’t enough the fur on their paws acts a fluffy built in snow shoe. Adorable and practical, I love it!

🐦 Ptarmigans: Feathered Footwear
Speaking of snowshoes, I found out that foxes are the only species to protect their feet from freezing in the winter. Ptarmigans, a partridge sized bird, grows extra feathers on their feet. Just like foxes this helps to walk across the snow without sinking.

🦬 Muskoxen: The Woolliest of Woollies
Muskoxen wear qiviut, a type of wool eight times warmer than sheep’s wool. It’s so soft and warm that people sometimes use it to make luxurious scarves. Muskoxen, however, prefer to keep their wool on their bodies. Not to say they wouldn’t be chick in a scarf too!