The Zoo

The Philadelphia Zoo joins Kids Corner monthly to explore the fascinating world found behind the gates of America's First Zoo!

Animals in the winter

The official start of winter is right around the corner. At this time of year we're all preparing ourselves for the chilly weather - getting out our hats, scarves and gloves! The Zoo is open all year and winter is one of the most beautiful times to visit the animals. They're ready for the cold days ahead and, in some cases, our animal staff lend them a hand.

Staying warm at the Zoo...

For those animals that aren't the biggest fans of the colder weather, we offer them lots of ways to stay warm.

Lions, cheetahs and jaguar all have "hot rocks" built into their exhibits. Just like you might curl up and a take a nap with an electric blanket, these big cats can snooze on fake rocks with heating elements built in. Look carefully, many of these fake rocks are hidden. For example, the giant termite mounds in the lion exhibit of Bank of America Big Cat Falls are hidden hot rocks!

Believe it or not, only four of the 17 penguin species come from cold weather habitats. The penguins at the Philadelphia Zoo are a warm weather penguin species from South America known as Humboldt penguins. They pair up in individual dens to stay warm on those cold winter nights.

Ever wonder where the prairie dogs go during the chillier weather? They have a 12-foot tunnel in their exhibit where they can burrow down underground out of the cold.

The giant otters have a luxurious heated pool which allows them to go out all year round. Their pool is heated to about 70 degrees every day.

Typically animals that are warm weather critters will go outside if the temperature is above 45-50 degrees and exhibit conditions are right. Many animals from warm climates do not have feet that are adapted for walking on ice and snow, so if an exhibit is icy and slippery it can be dangerous for them. In the winter, if conditions are right, animals are often given access to their outdoor areas, and they can decide if they would rather be inside or out.

The Zoo's nutritionist also makes changes to many of the animals' diets to help their bodies prepare for the cold weather. Some animals are fed more food so that they can build up a layer of fat to help keep them warm and provide more energy. Other animals actually become less active during the winter, and eat less, so their diets are actually decreased. Some even hibernate at the Zoo!

Lovin' winter weather at the Zoo...

Many animals at the Zoo love this time of year. The tigers, polar bears, snow leopards and red pandas - just to name a few - enjoy the brisk, cold days ahead. They especially like when it snows and are more active when the temperatures dip down.

Check out your local zoo to see what the animals are doing in the winter weather!

Animals in the Wild

There are a number of animals that thrive in the cold weather. They have adaptations that help them survive when the temperature dips. Some animals have an extra layer of fat (thick blubber) to keep them warm, while others grow "winter coats". Some animals such as snowshoe hares actually change color and become white to camouflage in the winter weather. Other animals would rather hibernate or migrate in the winter to avoid the cold.

Our winter residents...

There are many animals in our backyards that stick around during winter - everyone from birds to bears to bugs. The chickadee is one species of bird that does not migrate south, but stays in this region. Chickadees and other small birds survive the winter by allowing their body temperature to drop several degrees below normal during the night. In doing so, they use less energy, though short bursts of shivering keep their temperature from dropping too much. During the long winter nights, chickadees also group together in logs and tree cavities (such as nest boxes) in order to conserve heat. By grouping together in a confined space, chickadees are able to use their escaping body heat to warm the air around them.

Other winter residents are still in our backyards, just not very visible. There are true hibernators that go into such a deep sleep they are difficult to wake and may even appear dead. Their body temperature drops and breathing and heart rates slow down significantly. For example, a hibernating woodchuck's heart rate slows from 80 to 4 beats per minute, and its temperature drops from 98 F to as low as 38 F. However, even when the weather is severe, hibernators may wake up for short periods every few weeks to use their "bathrooms" and eat if food is available. Other true hibernators include the little brown bat, the eastern chipmunk and some species of ground squirrels.

The largest hibernators are bears. Although a grizzly or black bear's heart rate may drop from a normal of 40-50 beats per minute down to 8-12, its temperature drops only slightly, allowing it to wake up quickly. Bears are unique because, unlike other hibernators, they do not eat, drink or go to the bathroom at all while hibernating, which can be as long as six months.

Cold-blooded animals like fish, frogs, snakes and turtles have no way to keep warm during the winter. Snakes and many other reptiles find shelter in holes or burrows, and spend the winter inactive or dormant.

Water makes a good shelter for many animals. When the weather gets cold, they move to the bottom of lakes and ponds. There, frogs, turtles and many fish hide under rocks, logs or fallen leaves. They may even bury themselves in the mud. They become dormant. Cold water holds more oxygen than warm water, and the frogs and other amphibians can breath by absorbing it through their skin.

Insects have a variety of ways to deal with the winter weather. Different insects spend the winter in different stages of their lives. Many insects spend the winter dormant, or in "diapause." Diapause is like hibernation. It is a time when growth and development stops. The insect's heartbeat, breathing and temperature drop. Some insects spend the winter as worm-like larvae. Others spend the winter as pupae. Other insects die after laying eggs in the fall. The eggs hatch into new insects in the spring and everything begins all over again!

Worms also have an interesting way to survive the winter months. They migrate! No, they don't go south as many birds do, but they migrate deeper into the ground below the freeze line. They might go as deep as six feet, where they'll continue their normal daily activities until the weather warms in the spring.