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Today's Family Magazine

A look at how some animals survive northeast Ohio winters

Photo by Courtney Kempert

By Tom Koritansky, Natural Resources Manager, Lake Metroparks
If you have lived through a northeast Ohio winter, you know that dealing with the weather can be quite a challenge. Snowstorms and frigid temperatures can be enjoyable for some, but downright miserable for others. Luckily, no matter how one feels about winter weather, humans are able to seek shelter away from the elements. Although wildlife in our area cannot simply turn up the thermostat in their habitat when temperatures get cold, they do have ways to survive some of winter’s most difficult conditions. Wildlife that make their homes in area streams, ponds and wetlands are uniquely suited for the task.
Winter is a time of scarcity and dormancy for some, and wildlife must be adapted to survive long periods of cold temperatures and times when food is in short supply. Many of these animals like amphibians, reptiles and fish are cold-blooded and must use the surrounding environment to control their body temperatures. This means that cold-blooded animals are only as warm or cold as their surroundings, so they must be uniquely adapted to deal with extreme temperatures.

Some animals found in more aquatic habitats of Lake Metroparks, like some frogs and turtles, hibernate for the winter. To hibernate means to spend the winter in a state of dormancy. Aquatic frogs like the American bullfrog make their hibernacula (the place they will spend the winter under water) well hidden amongst debris but not buried. During hibernation, they enter a state of torpor where their metabolism slows down so that they use very little energy. They can remain in this state for months. Frogs must be in oxygen-rich water to survive the winter. Very cold water contains a lot of oxygen, and as long as the water is not frozen, frogs can absorb oxygen through their skin.

Frogs that are terrestrial or land dwelling will seek shelter under leaf litter, within crevices of trees or burrowed in soil. Wood frogs and spring peepers, for example, will secure themselves within deep crevices of logs and rocks. These frogs are well adapted to freezing and thawing repeatedly throughout the winter. When temperatures cool and approach freezing, their bodies are triggered to produce large volumes of blood sugar or glucose that act as a type of antifreeze. While most of the water in a frog’s body may freeze, this antifreeze will protect living cells. When frogs are frozen, they do not have a heartbeat, no circulation and very little nerve activity. Their eyes appear white because the lens freezes.

Like aquatic frogs, aquatic turtles adapted to cold climates also hibernate. Most aquatic turtles take refuge deep within ponds and settle in mud and debris at the bottom. Like frogs, turtles enter torpor using very little energy or oxygen. Turtles will get what little oxygen they need by absorbing it through the skin of their legs, throats or tails. Their hearts slow down so much that they may only beat once every few minutes! Painted turtles, for example, can survive submerged under water for as long as three months with very little oxygen.

Some fish survive the winter by greatly reducing their activity. They become very sluggish and almost inactive. Fish in moving water find areas to settle out of moving currents, behind rocks or in deep pools. Fish in ponds will group together and settle deep under water away from any ice or water that could freeze. Winter activity is highly variable by species. Some fish, such as trout, actually prefer cold water and are more active during the winter. Surviving the winter is especially tough for young fish as they may not be developed enough to handle such extreme conditions and may become prey for larger fish.

There are also many insects capable of surviving a northeast Ohio winter. Some insects migrate to warmer climates while others do not. Many insects undergo several distinct stages of development throughout their lives and different insects are adapted to overwinter in different stages. Some survive the winter as immature larvae protected by leaf litter, under the bark of trees or underground. Others like some dragonflies, mayflies and stoneflies spend the winter as nymphs and are active in ponds and streams. They feed through winter and become adults in the spring. Some insects overwinter in the pupal stage like silkworm moths. They emerge from their pupae as adults in the spring. A few insects lay eggs that can survive the winter. Insects that overwinter as adults often hibernate. Hibernating insects seek out a place to shelter for the winter and enter a resting state called diapause using very little energy. Some insects like wooly bear caterpillars, water striders and mourning cloak butterflies produce glycerol that acts as antifreeze to protect them from harsh temperatures.

While wildlife watching opportunities during winter may not be as fulfilling as summer, there is still plenty to appreciate about the natural world around us. Next time you venture to the parks, take a closer look at the ponds and wetlands. Even though they may appear lifeless, they are actually providing refuge to many organisms adapted to survive some of northeast Ohio’s harshest winter conditions.