While most familiar squirrel species are primarily active when the sun is up, there are specific reasons for this behavior and certain exceptions that lead to nighttime sightings. Understanding their natural rhythms helps explain when and why these rodents are observed.
Typical Squirrel Activity
Most common squirrel species, such as tree squirrels and ground squirrels, are diurnal, meaning their activity peaks during daylight hours. They typically emerge from their nests or burrows around dawn, with foraging for food being a primary activity in the morning and late afternoon. This daily routine involves gathering nuts, seeds, and berries, and engaging in playful interactions and nest building. Throughout the day, squirrels might take short naps to conserve energy.
As dusk approaches, these diurnal squirrels retreat to their nests, known as dreys, often constructed high in trees from twigs and leaves or within tree cavities. Ground squirrels, conversely, use burrows for shelter. At night, they rest and conserve energy for the next day’s activities.
Reasons for Nighttime Inactivity
The primary reason most squirrels are inactive at night relates to their vision. Diurnal squirrels possess eyes adapted for bright light, resulting in comparatively poor night vision. Their visual systems lack the high concentration of rod cells found in nocturnal animals, which are specialized for low-light conditions. This limited ability to see in the dark makes navigating their environment and locating food sources more challenging.
Another contributing factor to their daytime activity is the presence of nocturnal predators. At night, many formidable hunters become active, posing a threat to squirrels. These predators include owls, raccoons, foxes, coyotes, and bobcats, all with enhanced senses for hunting in darkness. By remaining in their sheltered nests, squirrels reduce their exposure to these threats. Additionally, the scarcity of accessible food sources in the dark encourages their daytime foraging patterns.
Unusual Nighttime Sightings
While most squirrels are diurnal, flying squirrels are a notable exception, being genuinely nocturnal. These squirrels have larger eyes with a higher concentration of rod cells, allowing them to navigate and forage effectively in low light. Flying squirrels are proficient gliders, using a membrane between their limbs to move between trees, and they search for food like nuts, seeds, fungi, and insects at night.
Beyond flying squirrels, a common squirrel might occasionally be observed at night under unusual circumstances. For instance, a squirrel could be disturbed from its nest by a predator or other disruption, prompting it to flee after dark. Extreme food scarcity might also cause a common squirrel to venture out at night to find sustenance, especially during colder months. Disorientation due to head injuries or illness can also lead to unusual nighttime activity, as an affected squirrel might struggle to find its way back to its drey. An injured squirrel might also be more vulnerable if it cannot retreat to safety.