Photograph by John Eastcott and Yva Momatiuk, Nat Geo Image Collection
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A male moose comes out of the bushes during the fall in the Alaska tundra

Photograph by John Eastcott and Yva Momatiuk, Nat Geo Image Collection

Fascinating ways animals prepare for winter

When fall arrives, people start pulling out their sweaters and snuggling up inside. Many animals also start preparing for winter. The shorter days signal critters from deer to birds to bears that it’s time to gather food and find mates. Check out some animals that get busy when the leaves begin to fall.

Lonely deer

For many members of the deer family, fall means it’s time to find a mate. That includes its largest species, the moose. Males of this usually solitary animal—which ranges across the northern United States (including Alaska), Canada, and northern Europe—look for females from September to mid-October.

Resting birds

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An Eared Grebe floats on lake in New Mexico.

As birds fly south for the winter, many species make pit stops on their journey. For instance, eared grebes take a break after traveling from places such as Oregon and Colorado. They gather by the thousands at Mono Lake in California and the Great Salt Lake in Utah to eat and shed their feathers. Other birds that take rest stops before continuing south include gulls, ducks, and shorebirds. Many birds rest and feed at these places, returning to the same spots each year.

Fat bears

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In fall, North American bear species start a process called hyperphagia, eating and drinking as much as they can to gain weight for their long winter hibernation. Gaining so much weight would be unhealthy for people, but scientists have found that grizzly bears are specially adapted to hibernate.

Hungry ladybugs

Many of the approximately 5,000 species of ladybugs—such as multicolored Asian lady beetles, which are invasive in North America—will fatten up on thousands of aphids and soft-bodied prey as fall arrives, says Mike Raupp, an entomologist at the University of Maryland. (An entomologist is someone who studies bugs.)

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The female ladybug lays sticky jellybean-shaped eggs and places them on the underside of leaves so they’re hidden from predators. She also makes sure tasty, pinhead-size insects called aphids live nearby so her babies can snack after hatching.

After this feast, the insects gather in a big group to wait out the long winter. Some prefer to hunker down in the cracks of rocks. Others will gather on the sides of houses. Predators usually don’t notice this ladybug heap, but if they do—and ignore their bright warning colors—watch out! The insects might turn to reflex bleeding, in which smelly bug blood called hemolymph seeps out of their “knees” to give the predator a mouthful of yuck.

“Hibernating” bird

While other birds fly south for the winter, the common poorwill of western North America and Mexico is having a “stay-cation.”

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A common poorwill blends into its surroundings in British Columbia, Canada.

These nighttime fliers are the only bird species known to go into a torpor—sort of like hibernation. They bring their body temperature down to 41˚F, then “hibernate” the way they nest: on the ground, where their mottled brown camouflage makes them almost invisible. Like mammals, they weigh the most before they go into their torpor. One researcher found the average poorwill torpor is about five days—but one especially sleepy bird slumbered for 45!

Text from "Fascinating ways animals prepare for fall" by Liz Langley for National Geographic News
Adapted by Laura Goertzel, NG Staff