Ground squirrels are common burrowing rodents known for their intricate burrows. These animals exhibit distinct activity patterns throughout the year, closely linked to environmental changes. Their emergence from burrows and periods of surface activity follow specific seasonal and daily rhythms for survival.
Spring Awakening
Ground squirrels are hibernators, spending a significant portion of the year in their burrows. Their emergence typically marks spring’s arrival. In many regions, this “spring awakening” can occur from late January to March, though some populations in colder climates or higher elevations may not appear until April or even May. Generally, male ground squirrels tend to emerge from hibernation approximately 10 to 14 days earlier than females. This signals the start of their active season, when they find mates and forage.
Daily Routines
Beyond their annual cycle, ground squirrels follow a predictable daily schedule. They are diurnal. Their peak activity times usually occur in the mid-morning and again in the late afternoon. During these periods, they are often seen foraging for food, engaging in social interactions, and maintaining their burrows.
Ground squirrels often retreat to their burrows during the hottest parts of the day, particularly when temperatures exceed 80°F. This helps them regulate their body temperature. They rarely venture out on overcast or damp days, preferring sunny conditions for their activities.
Factors Affecting Emergence
The precise timing of a ground squirrel’s emergence from hibernation is influenced by several environmental and individual factors. Temperature, both of the ground and the air, plays a substantial role. Warmer temperatures and the melting of snowpack typically trigger an earlier emergence. Conversely, prolonged wintry conditions or lingering snow can delay their appearance.
Geographical location also dictates emergence timing; ground squirrels in warmer, southern regions often emerge earlier than those in colder, northern areas. Beyond environmental cues, individual characteristics such as fat reserves, sex, and age can influence when a squirrel awakens. Heavier squirrels, for example, might enter hibernation earlier and emerge later, leveraging their stored energy.
Life Above Ground and Return to Burrows
Once above ground, ground squirrels focus on survival and reproduction. This active phase involves intensive foraging to replenish fat reserves, mating, and raising their young. Females typically produce one litter per year, with young emerging from the natal burrow after several weeks. Juvenile squirrels spend their first summer building fat reserves, as many may not estivate or hibernate during their first year.
As the active season progresses, typically in late summer or early fall, ground squirrels begin preparing for their return to dormancy. In hot, arid climates, some species, like the California ground squirrel, may estivate (a summer dormancy) due to extreme heat and scarcity of food or water. Most ground squirrels re-enter their burrows for winter hibernation, which can last five to nine months. During this time, their metabolism slows, and they rely on stored fat.