Wildlife in the Winter

By Sophie Bowater • January 2022


It gets pretty cold in the winter in some places around the country. Do you ever wonder how wildlife deal with the temperature changes that come with winter? I do. There are three different ways animals deal with the cold months:

1. Migration: Some animals take long trips to warmer areas so they can find the food they need to feed themselves. Many birds migrate, but some mammals do too like bats, caribou and even some whales follow the weather to find warmth and food in the winter seasons. Monarch butterflies also are big migrators.

2. Adaption: Some animals change with the seasons in turn adapting to the weather and temperature conditions. Most animals grow thicker coats or their fur changes color so they blend into the snow and are more protected from predators. In the winter, most rabbits turn white to blend in with the snow. Whitetail deer grow a grayish coat during the winter blending in with the color of forest tree trunks. Some animals store nuts and seeds like squirrels so they have plenty of food put away to last them for the winter.  

3. Hibernation: We all know that bears hibernate. What exactly is hibernation and how does it work? When an animal hibernates, their body drops into a deep sleep and their systems slow down to preserve energy and fat reserves. Bears, skunks, chipmunks and some species of bats all hibernate to conserve energy and wait until food sources are plentiful again.

I will touch on a few animals that have very interesting abilities to stay warm in the winter:

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Moose foraging in winter

MOOSE and ELK have an easier time than deer in the winters as they have long legs that are able to traverse through the deeper snow. Their legs are actually double the length of a deer and a bull moose can stand at 7 feet tall! This makes it easier for them to get vegetation that is higher up. Their bodies are much bigger than deer too so they can store more fat for the winters. 

DEER have an amazing ability to adapt to the cold. Their winter hair is hollow and helps them insulate better so they can maintain their body heat. If the temperature becomes super low, deer eat more and move less to conserve energy to keep warm. Also, when the temperatures get really cold, deer tend to come together in groups to bed down and keep each other warm. How smart!

BEARS work on building up their fat reserves in the late summer and fall so they can rest their very full and tired bodies into a den where they wait out the cold winter months. During the time of filling up their fat reserves, bears can eat upwards of 20,000 calories a day! Unlike true hibernating animals though, bears can wake up from their deep sleep during the winter. During their hibernation, they lose only 25 % of their strength. Humans would lose 60%. Unlike humans, bears recycle their urine. We expel a lot of nitrogen in the morning when we get up to pee. Bears recycle it into their blood, then to their  guts and onto the liver. The amino acids are made in the liver, and then the skeletal muscle is reunited.

BEAVERS are amazing builders. They will collect twigs, bark, and other food to last them for the winter and will cozy up in their amazing lodges during the cold winter months. They have very thick fur which is coated in oil that keeps them dry. Sometimes one will see steam rising from their lodges as they can be 35 degrees warmer than the outside air! As long as their food lasts, they will stay in their lodges all winter long.

REPTILES such as snakes, lizards, frogs, toads and newts almost bring their internal body to a complete stop in the very cold months.  This is known as diapause which is when the animal’s body stops developing, caused by a decrease in metabolic activity.  In this state, the animals use up just a small amount of their store of body fat and can survive for some weeks, barely alive. Wood frogs have a really cool adaptation. 65% of the water in their body freezes and they still survive! Most other frog species have to stay underwater or below the frost line, but wood frogs produce an antifreeze in their bodies and concentrate the antifreeze in certain organs of their bodies. This antifreeze prevents ice crystals from forming that would damage the wood frog.  Because of this amazing adaptation, wood frogs can live in extremely low temperatures.

BIRDS, just like other wildlife, stack on the fats during the summer and into the fall so they are prepared for their long, cold winter. Besides building their fat reserves, their feathers play a key role in keeping them warm as they trap pockets of air around their bodies. Birds need to have clean, dry and flexible feathers to maintain these layers of air. They keep their feathers clean by preening regularly. Some birds produce a special oil while others have special feathers but, in the end, birds know how to protect their bodies from the cold.  Preening helps birds keep a water resistant top layer and a toasty warm inner layer. Birds also like to cuddle together to share body heat which is definitely what I would do.

 


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