Squirrels, the bushy-tailed creatures often seen darting through parks and yards, lead complex lives. Despite their constant activity, these rodents spend a significant portion of their day resting. Understanding their sleep habits offers insight into their survival strategies and adaptability.
Daily Sleep Patterns
Squirrels generally sleep for an average of 12 to 15 hours per day, though this can vary depending on the species and environmental conditions. For instance, the gray squirrel typically sleeps for about 13 hours daily, often in intervals of two to three hours. While many squirrel species are diurnal, meaning they are most active during the day, others are crepuscular, showing peak activity at dawn and dusk. This pattern allows them to avoid predators active during full daylight or complete darkness.
Their sleep is considered polyphasic, meaning it occurs in multiple bouts throughout a 24-hour period, rather than a single long stretch like human monophasic sleep. Tree squirrels, for example, are active during the morning and afternoon, retreating to their nests for rest during midday lulls and at night. This segmented sleep pattern allows them to remain vigilant against threats while still getting necessary rest.
Where and How Squirrels Sleep
Squirrels select their sleeping locations with safety and comfort in mind. Tree squirrels, such as the eastern gray squirrel and red squirrel, commonly build nests called dreys high in trees. These spherical structures are constructed from twigs, leaves, and moss, placed in tree forks for support. They also utilize natural tree cavities or hollows as dens, which offer increased protection from predators and harsh weather.
Ground squirrels, as their name suggests, prefer to sleep in underground burrows, which provide insulation from temperature extremes and security from threats above ground. These sleeping quarters are essential for conserving energy and recovering from their active daily routines. Mammals generally experience both REM (Rapid Eye Movement) and non-REM sleep, which are crucial for physical restoration and cognitive function.
Factors Influencing Sleep
Several environmental and biological factors can influence a squirrel’s sleep duration and patterns. Seasonal changes play a significant role; for instance, fox squirrels spend more time in their nests during winter, accounting for about 77% of their day, compared to 66-68% in other seasons. Many common tree squirrels, like the eastern gray squirrel, do not truly hibernate but may enter periods of reduced activity or torpor during severe winter weather, sleeping for several consecutive days to conserve energy when food is scarce.
Food availability also impacts their sleep, as periods of abundance might lead to more frequent naps, while scarcity could necessitate longer periods of rest to conserve energy. The presence of predators influences their activity and sleep, driving them to be active during times when threats are less prevalent and to seek secure sleeping spots. Extreme weather conditions, such as very hot temperatures or heavy storms, can lead squirrels to stay in their nests for longer periods, altering their typical daily activity cycles.