Many desert animals are fossorial, which means they cope with extreme temperatures by concealing themselves in holes, or burrows, in the ground. To conserve energy when food and water are scarce, some desert species seek the safety of their dens and go into a dormant state, called hibernation in the winter and estivation during the summer or dry periods. Desert burrowers also retreat to their underground abodes to elude would-be predators.
Many desert-dwelling mammals of the order rodentia are fossorial, including the three ground squirrels found in the Sonoran Desert of North America -- the Harris’ antelope squirrel, round-tailed ground squirrel and rock squirrel -- all of which have strong claws designed for digging. Jerboas, a type of rodent found in Africa's Sahara Desert, also dig burrows, as does one of their predators, the small fennec fox. Fossorial mammals in the deserts of Australia include the spinifex hopping mouse, a rodent that covers the entrance to its burrow with grass, and the marsupial mole, whose embryos develop in an exterior pouch on the female's body. The pouch opens backwards and therefore does not get filled with dirt as the animal uses its powerful forelimbs to dig.
Desert reptiles that dig burrows include the venomous Gila monster of the Sonoran desert, also known to hide under rocks. Gila monsters live a largely sedentary life, especially in the winter, during which they remain in their burrows and rely on fat reserves in their tails for sustenance. Desert iguanas have a high tolerance for heat, but will burrow under the roots of creosote bushes in order to escape from predators. Desert tortoises, which live in the Mojave and Sonoran Deserts, are able diggers, thanks to their flat forelimbs. These ancient creatures, which can be up to 15 inches long, hibernate and spend 95 percent of their lives in their burrows, often in the company of several other individuals. Some desert snakes, like the venomous horned viper of the Sahara Desert, also burrow to escape from the sun.
The few amphibians -- cold-blooded animals that undergo a larval stage -- that survive in deserts do so by digging burrows. Examples include the Couch's spadefoot toad of the American Southwest, which has protrusions on its hind legs that allow it to dig. Couch's spadefoot toads estivate underground during droughts; at the sound of the summer rains, they emerge to feed on insects and reproduce. One meal can last them an entire year. The Sonoran Desert is also home to the northern casque-headed frog, which like the spadefoot, has digging apparatuses on its hind legs. When it goes into estivation, it sheds layers of skin that encase the animal to prevent dehydration.
Burrowing owls, found in a variety of habitats, including the deserts of North America, get their name from their penchant for nesting in underground dens created by rodents. They are known to line their nests with cattle dung. When it senses danger inside its burrow, a burrowing owl may emit a sound similar to that of a rattlesnake's rattle in attempt to fool and frighten its attacker. Burrowing owls eat smaller mammals, amphibians and reptiles and even insects.
- Arizona-Sonora Desert Museum: Ground Squirrels
- San Diego Zoo Animal Bytes: Gila Monster
- Arizona-Sonora Desert Museum: Desert Iguana
- Defenders of Wildlife: Burrowing Owl
- Britannica Online Encyclopedia: Jerboa
- Alice Springs Desert Park: Spinifex Hopping Mouse
- Australian Department of Sustainability, Environment, Water, Population and Communities: Southern Marsupial Mole
- Defenders of Wildlife: Desert Tortoise
- Arizona-Sonora Desert Museum: The Desert Tortoise - A Natural History
- Arizona-Sonora Desert Museum: Adaptations of Desert Amphibians and Reptiles
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