There are 38 species of North American ground squirrels in the world. They differ from tree squirrels by primarily foraging on the ground and nesting on or in it.
One species of ground squirrel is the California Ground Squirrel, Otospermophilus beecheyi. They’re common in the western U.S. and the Baja California Peninsula. They’re popular because they can be coaxed to come for food. However, in some areas, it’s now prohibited for fear someone may be bitten. Like other rodents, they must gnaw to keep their front teeth filed down—otherwise, they’ll overgrow and ultimately prevent them from being able to chew food properly. They don’t gnaw much on wood, but they chew bark. Their favorite foods are dandelions, plantain, clover, and garden veggies. These animals can climb but prefer the ground.
There are three Chipmunk (Genus Tamias) species and about 20 subspecies. All but the Siberian Chipmunk live in North America. Chipmunks are beneficial—they eat small rodents, spread seeds and fungi spores, and eat grubs and other insects. They’re cute and fun to watch, so most people welcome them into their yards. But they can be destructive by munching on plants and flower bulbs and digging numerous tunnel entrances. Chipmunks spend most of their time on the ground and live in underground burrows, but they’re also good climbers and can be seen in trees.
Can you spot the entrance to the chipmunk burrow? After digging their burrows, they carry away all excavated matter and camouflage the entrance. This one has used leaves, but other materials, such as leaves, sticks, and rocks, may also be used.
The Eastern Chipmunk, Tamias striatus, is one of the most widely distributed in the U.S. They inhabit, as their name implies, the eastern half of the country. In winter, they hibernate, but not deeply, and they sometimes leave their burrows on warm, sunny days. When hungry, they rely on a cache of food they store ahead in a separate chamber in their burrow. Most emerge from hibernation in early March.
This California Ground Squirrel, Otospermophilus beecheyi, is scolding the photographer. She probably has a burrow below the woodpile.
Pocket Gophers are a group of several species named for their large cheek pouches, or “pockets.” The pockets are fur-lined and can be turned inside out! The gophers stuff them with food for transporting back to their burrows. These animals are “larder-hoarders.” That means they store food at a single location—sometimes in huge amounts—to eat when food is less plentiful aboveground. (By comparison, tree squirrels are “scatter-hoarders” that hide their food in many places.) Pocket Gophers are found throughout N. A. and south to Central America. Most have brown fur that matches their habitat. If these guys move into your yard, you’ll know it! They leave mounds of dirt in their wake.
Woodchucks, Marmota monax, also called “Groundhogs,” have no trouble climbing up into trees, as you can see below. They’re one the few animals that go into true hibernation, and their body temperature may fall remarkably—to 39°F-40°F (3.9°C). In October, they dig a burrow below the frost line in a wooded or brushy area and move in. They emerge from March to April (earlier in warmer areas). Woodchuck is from the Algonquin name for them, “wuchak.”
You’ve likely heard this old tongue-twister: “How much wood would a woodchuck chuck if a woodchuck could chuck wood?” It’s said in fun, but it seems there’s an actual answer: Cornell University says a wildlife biologist measured the inside volume of a woodchuck burrow and estimated that 700 pounds (318 kg) of dirt had been chucked out of it. So he concluded that’s how much wood a woodchuck would chuck if it were chucking wood!
Ground squirrels often live communally in complex burrows 2.0-4.0 feet (0.6-1.2 m) deep and up to 30 or more feet (9.1m) long, with each individual typically having a separate entrance. Burrows are used for hiding, resting, rearing young, and storing food. For hibernating, too, in areas where winter is severe. Their tunnels and mounds can be a hazard to humans, livestock, plants, and even buildings.
Ground squirrels are on the list of many farmers and ranchers for eradication because of their tunneling and foraging. Researchers, however, believe they play an important role in controlling insect populations, seed dispersal, soil aeration, and providing habitat for other animals with their abandoned burrows. They’re prey for hawks, foxes, weasels, and rattlesnakes. Females sometimes try to fool rattlesnakes by chewing up shed snakeskin and licking it onto themselves and their pups to obscure their scent. A research study shows this does seem to fool the rattlers.
NORTH AMERICAN PORCUPINES (Erethizon dorsatum) predominantly inhabit forests and shrublands in the western and northern U.S. and Alaska, as well as a few eastern states and Canada. They’re mainly nocturnal, and loners, but may share a den in winter. They don’t hibernate but may stay in the den during lousy weather. Their dens are in hollow logs, tree cavities, caves, and rock piles. “Porcupine” comes from Middle French for “spined pig.” Pig isn’t a suitable name, based on what we know today, because they aren’t related to pigs. But “spined” certainly is. Here’s an interesting factoid: They’re good tree climbers but sometimes fall and get impaled on their own spines (also called quills)! Beneath their quills is an undercoat of fur next to their skin for warmth. Covering that are guard hairs.
Quills are modified hairs—as many as 30,000 of them! They’re hollow, sharp, barbed, up to 3.0 inches (7.6 cm) long, and hard to remove if you get struck. The Porcupines don’t throw them like darts; they just dislodge easily. Quills cover their body, except for the stomach and face, and are kept flattened unless needed. Porcupines are shy and non-aggressive, but when threatened, they turn their back, raise their quills, and slap their attackers with their tails. Needless to say, they have few predators!
PRAIRIE DOGS inhabit the Great Plains and Mexico. Very social, they live in family groups called coteries which usually contain an adult male, one or two adult females, and their young offspring. The coteries are grouped into wards (neighborhoods). Several wards make up a colony or town. The animals often greet one another by touching each other’s teeth, which gives the appearance of kissing.
Black-tailed Prairie Dogs, Cynomys ludovicianus, have complex calls to warn others about predators: what they are, how big, and how fast they’re approaching. Professor Con Slobodchikoff has done an extensive sound analysis of their calls and says the animals describe a human walking through their town essentially like this: “Here comes the tall human in the blue (shirt)” or “Here comes the short human in the yellow.”
Prairie Dogs were named by early settlers, who thought their calls sounded something like barking dogs. Habitat destruction by farmers, urban development, and routine poisoning and shooting by ranchers have reduced their population by 95 percent. They once numbered in the hundreds of millions and were possibly the most abundant mammal in N.A.