Mouse in the House

Cactus Mouse

Desert mice have long, soft fur (pelage), but can be identified by its absence on their ears, tails and hind feet.

A Desert Rodent Family Warms Up to its New Home at the Zoo

Visitors to Regenstein Small Mammal-Reptile House (SMRH) can be forgiven for overlooking one of the zoo’s newest animal families.

For starters, cactus mice (Peromyscus eremicus) are tiny. They average just 3 inches in body length with a 4-inch, sparsely furred tail.

Cactus mice are also noctural, foraging for seeds, insects and vegetation after dark. So animal care staff at SMRH keep their exhibit on a reverse cycle: dimly lit during the day to encourage active behavior and brighly lit at night for bedtime.

Peer closely through the glass, though, and you’ll spy a flurry of activity. The six females and two males in the colony—in residence since mid-May—dash about the rocks, branches and sand of their home at speeds impressive for their size. That trait comes in handy in their native desert home in the southwestern United States and northern Mexico, where it helps them evade predators like owls and rattlesnakes.

It’s also why SMRH curator Diane Mulkerin and fellow animal staff wanted to present the rodent species for the first time at the zoo.

“We have a colleague at the Phoenix Zoo who told us they had a mouse species that was very visible and active,” says Mulkerin. “He wasn’t kidding. Try and catch one!”

The cactus mice are skilled climbers. Though they live near the ground in burrows, rock crevices or piles of vegetation in the desert, they can scale rock walls, trees and shrubs with ease.

Like many desert mammals, cactus mice also have special adaptations that enable them to survive the hot, arid conditions of their native habitat. When temperatures rise during the day, they’re able to lower their metabolism and enter a state of torpor known as aestivation that allows them to survive on very little water. (The small amount of water they do drink likely comes from succulent plants.)

Water won’t be in short supply for the colony at the zoo. Neither will offspring. Breeding is expected to occur at a relatively continuous pace year-round, as it does in the wild where the species is abundant and common.

“We expect them to have two to three litters a year,” says Mulkerin. “But we'll have to see what happens.”

by Craig Keller • Published July 23, 2012

Learn More

Zoo Families
Packs, herds, troops and flocks—families come in all shapes and sizes at Lincoln Park Zoo. Learn more about the diverse living arrangements among our resident species, and get the inside story on the zoo's new gorilla bachelor troop in the Summer 2012 issue of Lincoln Park Zoo's award-winning magazine!


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