South of the zoo’s main grounds, wild animals adapt to winter by relying on natural habitat at the zoo’s Nature Boardwalk. In this prairie pond ecosystem, grasses and other native plants are brown and dry in winter, but that doesn’t mean the place has shut down.
“To us it may seem dead, but for the animals it’s providing a resource,” says Maria Jazmin Rios, coordinator of wildlife management at the zoo’s Urban Wildlife Institute. “It provides different habitats to support different animals.”
A wide variety of birds—from downy woodpeckers to white-breasted nuthatches—ﬁnd shelter among stalks and shrubs and forage for berries, dried seeds and insect larvae among plants, from snowberry to juniper.
Meanwhile, a surprising number of mammals are hard at work. “The only mammal that hibernates here is the chipmunk,” Rios says. Other animals, such as deer mice, slow down and doze in their nests and burrows, but rouse periodically to eat. Squirrels and rabbits are wide awake, hustling for a living throughout the cold months. “Rabbits will eat the roots of the plants,” Rios says. “They don’t hide food like squirrels. They have to forage.”
Small animals make meals for bigger animals. Coyotes, red foxes, and red-tailed hawks hunt along the boardwalk.
“Winter is one of the best times to go out and look for mammals,” Rios says. “There are fewer places to hide. You might see tracks in the snow.”
You probably won’t see frogs, snakes, or turtles, cold-blooded animals that rely on the environment to thermoregulate. In winter, green frogs and bullfrogs hibernate on the pond’s bottom, taking in oxygen from the water through their skin.
Snakes and turtles brumate, a process similar to hibernation that slows their metabolism. They stop eating and become inactive to conserve energy and avoid watchful predators. Garter snakes burrow below the frost line under rocks and plants. Painted and snapping turtles burrow headﬁrst in mud underwater or on land and absorb oxygen through their exposed cloacas—a multipurpose rear-end oriﬁce.
Learn more in the winter 2017 issue of Lincoln Park Zoo Magazine.
Illustrations by Ashley Bedore