March 7, 2025
As we are coming into warmer and sunny days in Manitoba, it is an exciting time for the animals in the province who will soon be waking from their many months of hibernation. There is a common misunderstanding that hibernating animals are completely asleep all winter, but that is not entirely the case.
Did you know that there are three main types of hibernation? This includes true hibernation, torpor, and brumation.
Hibernation is triggered by hormonal changes and reduction in daylight hours, which happens during the winter months. Hibernation also does not always mean continuous sleep.
A Long Winter’s Nap
- True Hibernating
These animals reduce their body temperature to match the local environment’s temperature (sometimes only a few degrees above 0°C), reduce their metabolism, and slow their heart rate. For example, arctic ground squirrels (sik-siks in Inuktitut) found in the northern regions of Manitoba are an excellent example of a true hibernator. They drop their body temperature below freshwater freezing temperatures! Their core temperature stays around -2.9°C and their neck and head remain at about 0.7°C! These small rodents will begin hibernation around September and can stay in this state for as long as 9-10 months.\
2. Torpor
Torpor is a period of inactivity during the coldest time of winter mixed with activity during warmer winter weather. Essentially, this is a state of hibernation with decreased physiological activity and reduced body temperature. This state allows animals to survive on reduced food availability that can last hours, days or even weeks! Imagine chilling in your cozy bed and only getting up when it’s warm, or you feel like getting a snack! For example, the Striped Skunk in Manitoba are torpor hibernators. They shelter in dens from mid-November through January. We know these animals are not a favourite for everyone; you can be sure that you are less likely to run into them in the winter!
3. Brumation
Brumation is quite similar to torpor but is used to describe the winter habits of reptiles and amphibians. These species often wake when they are hungry, when the weather is warmer or if they are disturbed. A fan-favourite example of a brumation hibernator in Manitoba is the common garter snake. Garter snakes in Manitoba will spend the entire winter below the frost line and will even venture further down into the ground if winter temperatures are extreme. On warmer winter days, you may be able to catch these slithery creatures basking in the sun for a few hours before returning to their brumation state. Learn more about Narcisse here.
(sourced from Inaturalist)
Of course, many animals in Manitoba have adapted to surviving the cold Manitoba winter months and do not need to take part in extreme hibernating habits. Like humans in the winter who bundle up and often seek the warmth of indoors during the winter months, some animals do not hibernate, but they do change their behaviour in winter. Examples of species in Manitoba whom do not officially hibernate include the arctic fox, beavers, white-tailed deer, moose, black-capped chickadees, and squirrels.
Another common misconception is that polar bears hibernate in the coldest winter months. Only pregnant female polar bears in Manitoba den for an extended period of time, which is not true hibernation. Once polar bear cubs are born in their winter den, mothers will nurse them until the outside temperature begins to warm and will embark on their great adventure on the polar ice. Though they do stay in a den to keep their cubs warm and safe, the amazing polar bear does not officially hibernate!
A Rude Awakening
As humans, an earlier spring might seem enticing, but hibernating animals are taking a hit from rising temperatures due to climate change. Climate change and human activities are causing winters to change faster than animals are able to adapt to. Hibernating animals run into problems when they wake up early and there are not enough resources to survive. This affects mating seasons, preventing animals from building up their fat storage, and resulting in more competition for food resources.
For example, according to a study conducted by Colorado State University, the Arctic Ground Squirrel female populations are now ending hibernation up to ten days earlier. Though ten days does not seem significantly earlier, in the grand scheme of things, “in terms of the climate, this is incredibly fast,” said study co-author Cory T. Williams.
The impacts of climate change on the common garter snake are not fully understood, but studies have shown that in the last 40 years, garter snakes are waking approximately two weeks earlier than usual.
For our smelly friend, the striped skunk, typically they will venture out of their dens in search of food when the weather becomes mild and their energy reserve becomes low. If you ever smell this furry friend in the winter or find that you’re seeing them more and more in the winter months, this is a good indicator that our winter months are increasingly becoming warmer and warmer each year.
Conclusion
As we continue to witness the changing season and warmer days in Manitoba, it is important to remember how climate change is impacting the natural rhythms of hibernating animals. The arctic ground squirrel, common garter snake and striped skunk are just a few examples of the amazing hibernating animals in the province. The challenges these wonderful animals are having because of climate change highlights the importance for us to better understand and protect our environment. As we enjoy the first signs of spring, we should remain mindful of the balance between nature, climate and human activity.