A TURTLE'S WINTER

A TURTLE'S WINTER

How Ontario Turtles Survive the Cold Months

What do Ontario's turtles do during the winter? It's not just a matter of survival, but a fascinating journey of adaptation and resilience that is essential for their existence.

Ontario is home to eight species of freshwater turtles, inhabiting diverse aquatic habitats like wetlands, lakes, rivers, and streams. These reptiles are active from April to October, while the colder months are spent in a dormant state—a process worthy of exploration.

This article focuses on Ontario's turtles while touching on other animals for context. Dormancy—the strategies and adaptations animals employ to endure harsh conditions—is a captivating subject. Though we've kept the details as concise as possible, the richness of the topic makes for a deep dive into the winter survival of these remarkable creatures.

DORMANCY AND ITS VARIANTS: BRUMATION VS. HIBERNATION

Dormancy is when an organism minimizes metabolic activity and halts active development, essentially entering a state of self-preservation. For mammals, this is often called hibernation. Turtles, however, undergo brumation, a reptilian equivalent. Both strategies help animals survive cold temperatures, limited food supplies, and predators, but they differ due to the animals' metabolic processes and temperature regulation methods.

During dormancy, animals reduce their body temperature, heart rate, and breathing rate to conserve energy. For example, mammals like woodchucks are "true hibernators," dropping their heart rate from 80 beats per minute to as low as 5. Conversely, bears, often incorrectly associated with deep hibernation, experience a lighter state and can be easily awakened.

WHY TURTLES BRUMATE

Turtles, being ectothermic (cold-blooded), cannot regulate their body temperature independently. Their body temperature fluctuates with the environment, so they bask in the sun to warm up or retreat to water to cool down. During winter, turtles enter a low-energy state where their metabolic needs decrease by up to 95%. Their heart may beat as little as once every 10 minutes, and they cease eating entirely.

Unlike mammals that rely on fat reserves during hibernation, turtles have a unique strategy. They depend on glycogen stores in their liver and muscles, a clever adaptation that minimizes energy expenditure and prevents the build-up of lactic acid, which can be fatal. The role of a turtle's shell in survival is equally remarkable, releasing calcium and magnesium to neutralize lactic acid during brumation.

WINTER HABITAT: A WATERY REFUGE

Triggered by shorter days and colder temperatures, turtles seek refuge underwater in lakes, ponds, or streams that do not freeze solid. They burrow into the muddy or sandy bottom, wedge between rocks, or use abandoned muskrat burrows. Though low in oxygen (hypoxic), these underwater habitats provide the stability turtles need to survive the winter months. Some species, like the painted turtle, are so well-adapted that they can endure completely oxygen-deprived (anoxic) environments.

HOW TURTLES BREATHE DURING BRUMATION

Turtles breathe in extraordinary ways during brumation. While they possess lungs, using them would require too much energy. Instead, they rely on cloacal respiration, absorbing oxygen through specialized structures near their tail. These structures, called cloacal bursae, are highly vascularized and extract oxygen from water. This efficient system allows turtles to remain submerged for months with minimal energy expenditure.

Other breathing adaptations include absorbing oxygen through skin, throat linings, or other mucus membranes. For instance, the Eastern Musk Turtle uses its tongue for aquatic respiration, while the Spiny Softshell Turtle, with its unique rubbery shell, prefers habitats with consistently high oxygen levels.

THE HATCHLINGS' FIRST WINTER: OVERWINTERING

Only a few centimeters long, painted turtle hatchlings often spend their first winter in their nest just below the frost line. Using a natural antifreeze to prevent ice crystal damage, these resilient babies emerge in spring, ready to navigate a world fraught with challenges, including predators and roads.

THE LARGER PICTURE: A DELICATE BALANCE

Every animal, including turtles, plays a crucial role in the ecosystems they inhabit. With the increasing challenges posed by climate change, their survival is at stake. Extended brumation periods, delayed springs, and unusual behaviors like mating under the ice are just a few ways these resilient creatures adapt. Yet, their future depends on our collective efforts to protect their habitats and mitigate human impact. It's a responsibility we all share and a cause that should motivate us to act.

CLOSING THOUGHTS

Ontario's turtles are master adapters, navigating the challenges of winter with ancient, finely tuned survival strategies. Their ability to endure months underwater, survive on minimal energy, and emerge in spring ready for the active season is a testament to their resilience. Understanding and protecting these remarkable creatures is an opportunity to marvel at nature and a vital step toward preserving the intricate ecosystems we all share.

If you have any questions or concerns about a turtle or nest, please phone or text Think Turtle Conservation Initiative at 647-606-9537 when you are with the turtle or nest. For additional information about helping turtles, we have a variety of platforms for you to choose from—check out our other web pages at www.thinkturtle.ca, follow us on Facebook, or read our WordPress Blog posts at https://thinkturtleconservationinitiative.wordpress.com.  

Thank you for being a friend to the turtles and for your dedication to protecting Ontario's species at risk and their habitat. Your efforts are truly appreciated and make a significant difference.