Squirrels are among the most recognizable small mammals, frequently observed moving with rapid, precise motions during daylight hours. As diurnal creatures, the majority of tree squirrel species, such as the common Eastern Gray Squirrel, structure their entire routine around the presence of the sun. They are primarily active between sunrise and sunset, relying on daylight for foraging and navigation. The question of when squirrels go to sleep is not tied to a fixed clock time but rather to the ever-shifting light levels of their environment.
The Diurnal Activity Pattern
A squirrel’s daily schedule is not a continuous stretch of activity but instead features two distinct peaks separated by a period of rest. These peaks occur during the crepuscular hours: the early morning just after dawn and the late afternoon leading up to dusk. This pattern is highly advantageous because the lower light levels allow them to forage while avoiding the intense heat of midday and the greater hunting pressure from birds of prey.
The morning rush is typically the most intense period of activity, driven by the need to replenish energy reserves after the overnight fast. This foraging phase begins right around sunrise, or sometimes even 30 minutes prior, as the squirrels wake and groom themselves before leaving the nest. As the sun climbs higher, a mid-day lull occurs, during which squirrels often take a prolonged nap or rest in the shade to conserve energy and avoid overheating.
Activity resumes in the late afternoon for a second, less intense peak of foraging and food caching before the evening retreat. When the sun dips below the horizon, the squirrels quickly return to their shelters, usually disappearing shortly after sunset. They rely on their daytime vision and generally lack the specialized sight needed to navigate safely in the dark, making nighttime reserved almost entirely for sleep and protection from nocturnal predators.
Environmental Factors that Shift Sleep Time
While the activity routine follows the light, the exact “bedtime” and “wake-up time” are flexible and heavily influenced by external variables. Seasonal changes in day length cause significant shifts in the duration of the active day. In the summer, the long days allow for extended foraging, while the shorter days of winter mean an earlier retreat and a later start to the day.
During the coldest parts of winter, the daily activity of tree squirrels is significantly reduced, sometimes to only a few hours around midday when temperatures are highest. They may remain inactive in their nests for extended periods during severe weather to save energy, though they do not truly hibernate like some ground squirrel species. Conversely, in extremely hot climates, squirrels may enter a state called estivation, which involves prolonged inactivity in cool, underground burrows to survive high temperatures and drought.
Weather events also cause immediate adjustments to the schedule, forcing an early “bedtime” or a delayed awakening. Heavy rain, snow, or high winds will prompt a squirrel to remain secured within its insulated nest rather than venturing out. Food availability also affects the timing of rest; for example, when nuts are abundant in the autumn, squirrels may extend their active hours to maximize their caching efforts.
Resting Locations and Shelter
When a squirrel retreats to sleep, it seeks safety and insulation in one of two primary types of shelter. The first is the drey, a bulky nest constructed from interwoven twigs, dry leaves, and moss, typically built high in the forks of tree branches. This structure serves as a warm, private spot for general rest, raising young, and sleeping during the warmer months.
The second type of shelter is the tree cavity or den, a natural hollow found inside a tree trunk or a large limb. These dens offer superior protection and insulation against the cold and predators, making them the preferred location for winter rest. Multiple squirrels may share a cavity during cold spells to pool body heat and enhance warmth. These shelters are fundamental to a squirrel’s survival, providing a secure place to rest and recover.