Thu. Dec 7th, 2023
Snowshoe Hare

Today’s post was written by Connor Oke, Marketing Intern at Ontario Parks, using information provided by Mark Read, a senior ranger on Discovery in Murphy’s Point Provincial Park.

If Canada is known for anything, it is our long, cold winters.

Wild animals depend on evolution and natural adaptations to survive until spring. The strategies they have developed are varied and simply incredible.

Here are six species, showing six different ways Ontario Parks wildlife spends the winter:

Turtles: life at the bottom of the lake

Normally, turtles use their lungs to breathe. However, they spend the winter submerged at the bottom of frozen lakes and ponds.

So how do they get the oxygen they need?

Closeup of a Midland Painted Turtle in Bonnechere Provincial ParkMidland Painted Turtle in Bonnechere Provincial Park

You see, a turtle’s body temperature changes with its environment. At the bottom of a lake, the temperature can drop to 4ºC. This causes a turtle’s metabolism, and in turn its need for energy and oxygen, to plummet.

Therefore, turtles are able to obtain the small amounts of oxygen they need through a process called “cloacal respiration.”

Simply put, they breathe through their asses.

The skin there is soft and thin and naturally exchanges oxygen and carbon dioxide with water.

snapping turtle in waterSnapping Turtle in Awenda Provincial Park

However, sometimes oxygen levels are reduced beneath a frozen lake. In these situations, some turtles may switch to a type of metabolism (anaerobic respiration) that does not use oxygen at all.

This can be dangerous because it causes a buildup of lactic acid, but some turtles, such as snapping turtles, can even neutralize it using the calcium in their shells.

Marmots: true hibernators

According to myth, if a groundhog sees its shadow on February 2, it means another six weeks of winter. That may not be true, but the interesting thing about groundhogs is that they are one of the few true hibernators in Canada.

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Photo: Simon Lunn

As winter approaches, groundhogs retreat to burrows below the frost line and enter a long period of inactivity. His body temperature drops from 35ºC to 6ºC and his heart rate drops from 100 beats per minute to just 15 beats per minute. They breathe only once every five or six minutes.

During this time, they survive on fat reserves and their total body mass can be reduced by half.

Common Green Darners: migrating like monarchs

Monarch butterflies may get all the attention for their seasonal flight south, but common green dragonflies have a similar way of dealing with winter: abandoning it altogether.

In fact, the Green Darner’s migratory pattern resembles that of the Monarch in many ways. Just as the Monarchs make their journey over several generations, the Green Darners divide theirs into three.

Closeup of Common Green Darner DragonflyCommon Green Darner in Rondeau Provincial Park

Around February, a first generation of Green Darners in Texas or Mexico will begin flying north, where they will lay their eggs in ponds and then die. When the new generation hatches, some will fly south that same year, while others will spend the winter in the north as nymphs.

Dragonflies that head south will also lay their eggs and die, giving way to a new generation that will spend their entire lives living in the south. So, the cycle continues.

Woolly bear caterpillars: frost resistance

The Isabella tiger moth, better known as the woolly bear moth, is unusual in that it overwinters as a caterpillar. These caterpillars hatch in the fall and feed well into the season before sheltering under logs and piles of leaves to stay warm.

Woolly bear caterpillar on a log in Mark S. Burnham Provincial ParkWoolly bear caterpillar on a log in the fall in Mark S. Burnham Provincial Park

Still, even under all that insulation, temperatures can dip below freezing. For the average caterpillar, this would be a death sentence. Woolly bears, however, produce an antifreeze in their blood called glycerol. With this, they can reach temperatures as low as -8ºC without damaging any cells.

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When spring finally arrives, the caterpillars thaw before continuing to feed for a few weeks. Then, in late spring, they pupate before turning into beautiful moths.

Bats: facing new threats

Like groundhogs, five of Ontario’s eight bat species take refuge during the winter to hibernate (the other three migrate south). Your metabolism, heart rate, and breathing slow during this time.

Bats with white nose syndrome.Bats with white nose syndrome

Unfortunately, an introduced disease called white-nose syndrome is putting hibernating bats at risk. It is a white fungus that spreads across the faces and wings of bats, irritating them and waking them up early. While awake, they use up crucial fat reserves meant to help them survive the winter.

Parks, including Pinery Provincial Park, are conducting extensive research into this threat.

Snowshoe hares: blending in

Snowshoe hares are aptly named: Their huge hind legs provide them with a large surface area, like a snowshoe, allowing them to move quickly over the snow and escape predators.

But that is not its only winter adaptation. Aside from the tips of their ears, snowshoe hares turn completely white, which helps them blend in with the snowy surroundings. The receptors in your eyes, which are sensitive to the length of the day, register the moment of the color change.

Snowshoe hare in summer and winter.Snowshoe Hare in Lake Superior Provincial Park

As daylight decreases and winter approaches, the receptors cause a reduction in the production of the pigment melanin, which gives the hare’s skin and coat its dark color. This turns the fur into a natural snowy camouflage. Good luck spotting them now!

Learn more about the winter adaptations of our wildlife.

These are just a few examples of the adaptations Ontario animals use to survive the winter.

Did you know that black bears can give birth during their hibernation process? Or that birds like ducks, geese and swans can prevent heat loss by cooling the blood reaching their feet?

But of all the ways animals survive the winter, frogs might be the most interesting. Check out our full article on them here.

Do you want to learn more about the animals in our parks? Watch our Discovery programs, in parks and online!