Squirrels spend most of their waking hours doing just a few things: searching for food, hiding it, eating, keeping watch for predators, and maintaining their nests. That short list understates how rich and complex these behaviors actually are. A squirrel deciding where to bury an acorn is solving a spatial memory puzzle, and one screaming from a branch is broadcasting surprisingly specific information about the type of threat it has spotted. Their daily routines shift with the seasons, differ between species, and look quite different in a city park than in a remote forest.
A Typical Day for a Tree Squirrel
Most common tree squirrels, like the eastern gray squirrel and the fox squirrel, are diurnal. They wake around sunrise, become most active in the first few hours of morning, and often have a second burst of activity in the late afternoon. The midday hours tend to be quieter, especially in warm weather, when squirrels retreat to their nests or stretch out on a cool branch. This bimodal pattern (active at dawn and dusk, resting in between) is familiar to anyone who watches a backyard feeder, and it holds across a wide range of tree-dwelling species.
Ground squirrels, by contrast, tend to stay active more steadily throughout daylight. Flying squirrels flip the script entirely: they are nocturnal, emerging after dark and doing most of their foraging and socializing at night. So “what squirrels do” depends heavily on which squirrel you mean. The rest of this article focuses mainly on the tree squirrels most people encounter, while noting where ground and flying squirrels differ.
Foraging and the Art of Caching
Food acquisition dominates a squirrel’s time budget. Tree squirrels eat a varied diet of nuts, seeds, tree buds, bark, fungi, fruit, and the occasional insect or bird egg. But gathering food is only half the job. Squirrels are famous for burying nuts and seeds to retrieve later, and the strategy they use depends on where they live and what food is available.
There are two broad approaches. Larder hoarding means gathering food into one big central stockpile, usually defended fiercely. Scatter hoarding means burying individual items across dozens or even hundreds of separate locations. Red squirrels and Douglas’s squirrels living in moist coniferous forests typically defend territories centered on a single large cache, maintaining home ranges that don’t overlap with their neighbors. But when red squirrels live in deciduous forests, where food sources are different, they switch to scatter hoarding and their home ranges start to overlap.
1Ethology. Spacing Behavior of a Non‐Larder‐Hoarding Tamiasciurus: A Study of Mearns’s Squirrels in Xeric Coniferous ForestsEastern gray squirrels are scatter hoarders almost exclusively. A single gray squirrel may bury thousands of nuts in a season, each in its own shallow hole, and research suggests they remember many of these locations using spatial memory rather than smell alone. They also employ deceptive tactics: if a squirrel notices another watching it bury a nut, it may dig a fake hole and pretend to deposit food there, then carry the real nut to a different spot. This kind of tactical deception is unusual in animals and points to a level of cognitive flexibility that researchers find genuinely impressive.
Not every cached item gets recovered. Estimates vary by species and environment, but a meaningful fraction of buried nuts are never dug up. Those forgotten caches sprout into new trees, which makes squirrels among the most important seed dispersers in temperate forests. An oak forest owes a surprising amount of its regeneration to squirrels that buried acorns and never came back for them.
How Squirrels Talk to Each Other
Squirrels are far noisier than most people realize, and their vocalizations carry specific information. Eastern gray squirrels produce a mix of calls researchers have categorized into distinct types, including short, sharp “kuks,” longer “quaas,” and drawn-out “moans.” These aren’t just generic alarm sounds. The rate, duration, and structure of these calls contain information about both the type of threat and the internal state of the caller.
2Adaptive Behavior. Hidden Markov models of eastern gray squirrel (Sciurus carolinensis) alarm callsGray squirrels also pair their calls with tail movements, and the combination is what conveys the clearest message. Research on their joint vocal and tail signals found that broad tail movements called “flags” were associated primarily with terrestrial threats like cats and dogs, while moans were triggered mainly by aerial threats like hawks. Other call types and tail twitches appeared in both situations and didn’t reliably distinguish between predator types on their own.
3Behaviour. Joint tail and vocal alarm signals of gray squirrels (Sciurus carolinensis)This pattern of predator-specific alarm calls shows up in ground squirrels too. Arctic ground squirrels produce a short, broad-frequency “chat” sound and a longer descending “whistle.” When a ground predator approaches, squirrels give a three-note chatter. If the predator gets close enough to force a retreat into a burrow, the chatter escalates to five or more notes that fade in intensity. But when an aerial predator appears, the squirrel switches to a single whistle that resembles a bird’s alarm call, repeating it every six to eight seconds if the predator lands nearby.
4PubMed. Characteristics of arctic ground squirrel alarm callsThe fact that both tree squirrels and ground squirrels have evolved separate signals for aerial and ground threats tells you something about how important predator identification is. A squirrel that hears the wrong alarm and looks up instead of down could pay with its life. These communication systems are not casual chatter; they are survival infrastructure refined over millions of years.
Nest Building and Maintenance
Squirrels invest real time and effort in their shelters. Tree squirrels build two types of nests. The most visible are dreys, which are the messy-looking balls of leaves and twigs wedged into tree forks. A drey has more structure than it appears from the ground: it typically features an inner chamber lined with softer material like shredded bark, moss, or dry grass, insulated by a thick outer shell of woven twigs and leaves. The second type is a den inside a tree cavity, which offers better insulation and protection from wind and rain. Squirrels prefer cavities when they’re available and often use dreys as backup shelters or summer nests.
A squirrel usually maintains several nests within its home range and rotates between them. Switching nests helps reduce parasite loads, since fleas and mites build up in bedding material over time. Females with young may move their litters from one nest to another if they sense a threat or if the nest becomes infested. Watching a mother squirrel carry a baby in her mouth across a stretch of open ground to a new nest is one of the more dramatic everyday squirrel behaviors.
How Squirrels See the World
Squirrel senses shape everything about how they go through their day. Their vision is better than many people assume. Tree squirrels have dichromatic color vision, meaning they see two primary color channels rather than the three that most humans use. Studies of the tree squirrel retina found a spectral neutral point at about 500 nanometers, which places their vision in a similar range to a person with red-green color blindness.
5PubMed. Spectral mechanisms in the tree squirrel retinaThis means squirrels can distinguish blues and yellows well but have a harder time with reds and greens. For a forest-dwelling animal, though, this isn’t much of a handicap. Their eyes are large relative to their skull size, giving them a wide field of view that’s excellent for spotting movement, which matters more than color when a hawk is diving toward you. They also have good peripheral vision, so they can monitor threats from multiple directions while foraging with their heads down.
Smell plays a major role in food recovery. Despite the evidence that squirrels use spatial memory to find cached nuts, they also rely on scent, especially when searching for caches buried by other squirrels. Their sense of smell is acute enough to detect a buried nut through several inches of soil and, in winter, through a layer of snow.
Squirrels in Cities
Urban squirrels behave differently from their rural counterparts in ways that go beyond just being comfortable around people. Research on fox squirrels found that animals in urban environments show reduced vigilance and anti-predator behavior compared to their rural peers, a pattern consistent with habituation to humans. Importantly, these urban squirrels still responded strongly to cues from natural predators like hawks and raccoons, suggesting that living near people doesn’t dull their survival instincts across the board. They learn to tune out harmless stimuli while staying alert to genuine threats.
6bioRxiv. Urban fox squirrels exhibit habituation to humans but respond to stimuli from natural predatorsA separate study of fox squirrel populations across sites with different levels of human density found that the biggest behavioral difference was a trend toward higher sociability in areas with more people. Squirrels in busier areas weren’t measurably bolder, more aggressive, or more active; they were just more tolerant of being near other squirrels.
7Journal of Mammalogy. Behavioral variation among Fox Squirrel (Sciurus niger) populations in urban environmentsThis makes intuitive sense. In a park where food is concentrated around trash cans, picnic areas, and bird feeders, the cost of being close to another squirrel drops because food is abundant and clumped. In a forest, where every nut you miss is a nut your neighbor gets, keeping your distance pays off more. City squirrels have essentially adjusted their social thermostat to match the economics of urban food distribution.
Urban squirrels also adjust their diets opportunistically. They eat pizza crusts, discarded granola bars, and the occasional French fry, though nuts, seeds, and natural plant material still make up the bulk of their intake even in cities. The nutritional consequences of a junk-food-supplemented diet are not well studied, but squirrels in parks with heavy human food waste do tend to be heavier than those in more natural settings.
Seasonal Shifts in Behavior
Squirrel behavior changes dramatically with the calendar. In autumn, caching activity ramps up to an almost frantic pace. Tree squirrels spend a huge proportion of their waking hours gathering and burying food, building up the scattered reserves they’ll depend on through winter. Their bodies change too: they put on fat, and their fur thickens into a denser winter coat.
Winter itself looks different depending on the species. Tree squirrels like grays and fox squirrels do not hibernate. They remain active all winter, emerging from their nests on all but the most brutal days to dig up cached food. On extremely cold days, they may stay in the nest for extended periods, huddling together for warmth in the case of species that tolerate communal nesting. Ground squirrels, by contrast, are among the deepest hibernators in the mammal world. Species like the Arctic ground squirrel can drop their body temperature below freezing during hibernation, entering a state of suspended animation for months at a stretch. Their daily “habits” during that period amount to essentially nothing: they are physiologically offline.
Spring triggers a shift toward reproduction and territory defense. Males become more active, ranging widely to find receptive females. Mating chases, where several males pursue a female through the treetops in a chaotic high-speed scramble, are one of the most conspicuous squirrel behaviors of late winter and early spring. Females, once pregnant, focus on preparing a nest for their litter. Most tree squirrel species produce one or two litters per year, with litter sizes typically ranging from two to five young.
When Squirrel Species Compete
Not all squirrel behaviors play out within a single species. Where different species share habitat, competition can reshape daily life for both. The most extensively documented case involves eastern gray squirrels and Eurasian red squirrels in the United Kingdom, where the introduced gray has driven red squirrel populations into steep decline.
Long-term research found that gray squirrels affect red squirrel fitness in several ways. Fewer female red squirrels produced litters in summer when gray squirrels were present, and fewer females managed to produce two litters in a year. Red squirrel recruitment, meaning the rate at which young animals survive and join the breeding population, dropped as gray squirrel density increased. Individual red squirrel females in sites shared with grays had lower body mass, which in turn reduced their reproductive output. Over time, this steady drag on breeding and survival leads to population decline and, eventually, local extinction of the red squirrel.
8Journal of Animal Ecology. Alien species and interspecific competition: effects of introduced eastern grey squirrels on red squirrel population dynamicsThe competition isn’t dramatic in day-to-day observation. Gray squirrels don’t chase red squirrels away in obvious confrontations. Instead, the effects are subtler: grays are more efficient foragers for certain food types, they raid food caches made by reds, and their presence reduces the resources available to red squirrel juveniles during the critical growth period. It’s a slow squeeze rather than a battle, which is partly why it went unrecognized for so long.
Grooming, Play, and Other Quiet Behaviors
Foraging and vigilance get most of the attention, but squirrels spend a meaningful chunk of their day on less dramatic activities. Grooming is a regular behavior, both self-grooming with teeth and claws and social grooming between individuals that share a nest or home range. Keeping fur clean and free of parasites is genuinely important. Squirrels host fleas, ticks, bot fly larvae, and various mites, and regular grooming helps manage these hitchhikers. Some species have specific grooming rituals, like cheek rubbing against branches, that may serve dual purposes of cleaning and scent-marking.
Young squirrels engage in play that looks a lot like the play behavior of other mammals: chasing, wrestling, and mock fighting. Play in juveniles likely serves the same function it does in other species, building coordination, social skills, and familiarity with the physical environment. Adult squirrels play less, but even adults occasionally engage in what looks like recreational chasing, especially in spring when energy levels are high and mating season brings squirrels into frequent contact.
Sunbathing is another behavior that catches people off guard. Squirrels will sometimes lie flat on a branch or even on the ground, splayed out with their belly pressed against the surface. This “splooting” posture is a heat-regulation strategy: pressing the belly against a cool surface helps dump excess body heat. It looks alarming if you’ve never seen it before, like the squirrel is injured or dead, but it’s perfectly normal warm-weather behavior.
Why Squirrels Chew on Everything
If you’ve ever found a squirrel gnawing on your deck railing, car wiring, or plastic bird feeder, you’ve witnessed one of the less charming squirrel habits. Squirrels are rodents, and like all rodents, their incisors grow continuously throughout their lives. They need to gnaw on hard materials regularly to keep their teeth worn down to a functional length. If they don’t, the teeth can overgrow and cause serious problems.
This biological imperative means squirrels will chew on wood, bone, antler, plastic, soft metals, and electrical insulation with equal enthusiasm. They aren’t eating these materials; they’re using them as dental maintenance tools. The damage to human property is a side effect of a behavior that, in a forest, would be directed at bark, dead branches, and the hard shells of nuts. In an urban setting, the available chewing surfaces just happen to include things people care about. This is one area where understanding squirrel behavior directly informs practical decisions: protecting wiring with hard conduit and bird feeders with metal baffles works because it accounts for what the squirrel is actually trying to do.