The common image of a squirrel is an agile, bushy-tailed rodent leaping through tree canopies, typically belonging to the Sciurus genus. However, the wider biological family, Sciuridae, includes over 200 species that share a basic body plan, leading to frequent misidentification. Many of these animals possess similar size, coloration, and rodent characteristics, making it challenging to distinguish a true tree squirrel from its lookalikes. The primary differences often come down to subtle visual cues, specific behaviors, and preferred habitat.
The Striped and Smallest Lookalikes
The most common source of confusion is the small, striped mammal that looks like a miniature version of its larger cousin. These animals, belonging to the genus Tamias, are noticeably smaller than most tree squirrels, weighing only about four to five ounces. Their most distinguishing feature is the presence of prominent stripes, typically five dark bands running down their back and flanks, often extending onto the face.
This striped pattern is a reliable visual identifier, as most true tree squirrels display uniform fur coloration, such as gray, red, or brown, without distinct striping. Behaviorally, these smaller lookalikes are primarily terrestrial, spending most of their time foraging on the ground and living in extensive underground burrows. They are frequently observed stuffing their large cheek pouches with seeds and nuts, an adaptation that allows them to transport food back to their caches. Tree squirrels, by contrast, typically carry a single nut in their mouth and construct their nests, called dreys, high up in tree cavities or branches.
The Urban Climbers Mistaken for Squirrels
Another group often mistaken for tree squirrels in urban environments are agile, climbing rodents that share similar gray or brown fur coloring. The key to differentiating these animals, particularly the Roof Rat (Rattus rattus), lies in a close inspection of their tails, snouts, and activity patterns. A tree squirrel is defined by its thick, heavily furred, and bushy tail, which serves multiple functions, including balance and warmth.
The rat possesses a long, thin, and largely hairless tail that often appears scaly. The shape of the head provides another clue: the tree squirrel has a blunter snout and a rounder face, while the rat features a more pointed muzzle and proportionately smaller eyes. Tree squirrels are diurnal, meaning they are active during the day. Climbing rodents are primarily nocturnal, meaning an animal seen actively foraging in a tree during daylight hours is far more likely to be a squirrel.
The Non-Arboreal Cousins
The Sciuridae family also includes a diverse array of terrestrial species that are genetically related to tree squirrels but exhibit a different lifestyle. These ground-dwelling species include the smaller Ground Squirrels and the much larger Marmots. Ground Squirrels, such as the California Ground Squirrel, have a less bushy tail than their arboreal counterparts. This is consistent with their need to move efficiently within underground burrows.
Their behavior centers around digging, with burrows serving as shelter, nursery, and food storage. When startled, a Ground Squirrel will instinctively dart toward its underground home rather than scrambling up a tree, a clear behavioral distinction. Marmots, the largest members of the squirrel family, present a different challenge for identification due to their sheer size, sometimes reaching the size of a house cat. They possess a stockier build and robust legs with enlarged claws adapted for digging, a stark contrast to the slender, nimble form of a tree squirrel.