The name "ground squirrel" encompasses many burrowing rodents such as the Richardson's ground squirrel, round-tailed ground squirrel, Harris's antelope squirrel and Columbian ground squirrel. Ground squirrels are opportunistic omnivores whose diet consists mostly of grasses and vegetation, seeds, nuts, berries and grains, plus worms and insects for protein. Ground squirrels kept as pets, in zoos or in a rehabilitation situation thrive on a diet of rodent pellets with seeds and nuts supplemented with hay, vegetables and insect protein.
Seeds and Grains
Ground squirrels in the wild forage throughout the day. taking available seeds, nuts and grains, often hiding the food in a cache. In captivity, they eat a pellet made especially for squirrels or prairie dogs. Some people who keep ground squirrels make their own squirrel diet by mixing a commercial hamster or gerbil food with timothy hay-based rabbit pellets. Pet ground squirrels also enjoy cooked brown rice as a treat.
Vegetables and Fruit
In the wild, ground squirrels munch an assortment of vegetation and fruits depending on the season and what is available in their habitat. According to the Arizona-Sonora Desert Museum, the round-tailed ground squirrel eats succulent green vegetation such as wildflowers, cactus flowers and fruit, ocotillo flowers and mesquite leaves. The Harris’ antelope squirrel eats less green vegetation and more fruits such as cholla, barrel cacti, prickly pear and mesquite beans. Pet ground squirrels enjoy leafy greens such as romaine or redleaf, spinach, parsley, bok choy, collards and broccoli. Healthy treats include raisins, carrots, berries and apple.
Insects and worms make up most of the ground squirrel's dietary protein. According to Texas Parks and Wildlife, the Mexican ground squirrel especially enjoys meat and will feast on carrion when available. Ground squirrels have been known to invade the nests of birds or mice. In captivity, ground squirrels readily eat crickets and mealworms, sold in most pet stores.
Grass or Hay
Ground squirrels eat many native grasses, whatever is available in their habitat. In captivity, you can offer pesticide-free, fresh-cut grass or timothy hay for gnawing.
In the wild, ground squirrels burn many calories spending their day foraging for food, digging and maintaining burrows and running from predators. In captivity, obesity is common with these animals, so free-feeding is not recommended. A couple of tablespoons of dry food supplemented by a small salad daily keeps ground squirrels a healthy weight. Fruits, brown rice and insects can be given as treats.