How animals survive the winter
Humans often hole themselves up in their houses to survive the winter in front of the fire with hot chocolate. However, animals have to survive the frigid chill outside in the elements, and they have different ways of dealing with the change in seasons.
Let's take a quick look at how these Iowa animals survive. Click the link under each snippet to read a more in-depth post about that specific animal.
White-tail deer
Deer stock up on food in the fall to increase their fat stores for the winter, and they also grow a special winter coat that insulates them as well as helps them absorb more of the sun's heat.
(Read more ways deer survive winter here)
Bats
USFWS/Ann Froschauer
Iowa’s two most common bats, and those that you would find in Dickinson County, are the little brown bat (Myotis lucifugus) and the big brown bat (Eptesicus fuscus). Both of these bats hibernate through the winter.
Hibernation means that a bat’s body slows down, including its metabolism, heart rate and breathing rate, so that it can survive a long time without food. A bat’s heartrate will drop from 200-300 beats per minute to about 10 beats per minute, and it can go several minutes without breathing. They can stay in this state for up to a month in the winter, mixing that with periodic cycles of normal activity.
(Read more about how hibernation helps bats survive here)
Garter snakes
To survive the winter, garter snakes will find a safe and snug place underground. They may look for a natural cavity or use a rodent burrow. They also find hibernation areas under rock piles or stumps. Sometimes, they may even look for warm places inside structures and have been found in basements. They can fit through a half-inch wide crack, so make sure to seal up any foundation cracks or window gaps to ensure that snakes do not get in your house in the winter.
(Read more about how garter snakes hibernate in groups to help them survive)
Monarch butterflies
Most people familiar with monarch butterflies know that they migrate to central Mexico to overwinter.
You can read in-depth how monarchs find their way here, but in general, they use their circadian rhythm to orient themselves with the direction of the sun and also use the earth’s magnetic field to fly toward the equator.
Muskrats
Photo: Tom Koerner/USFWS
Muskrats do not hibernate during winter, and they also don’t store food in their lodges like beavers do. That means that they need to find food and eat daily, even in cold weather.
They still live in their main lodges, but ice covering the rest of its habitat restricts it to finding food underwater. Yet, it still needs to breathe so it uses something called push-ups to solve both problems.
(Read about how muskrats survive underwater in the winter)
Turtles
A turtle's metabolism slows down as it spends its winter underwater, absorbing oxygen from the water that passes over its body.
(Read more about how these processes work here)
Fish
The fish in the Iowa Great Lakes eat enough to stay alive, but their body processes slow down in the frigid water. They even need less oxygen in the cold water.