Squirrels definitively have babies, which are commonly referred to as kits, pups, or kittens. Reproduction is a significant part of the life cycle for tree squirrels, such as the Eastern Gray squirrel, which populates many urban and forest environments. This process involves specific seasonal timing and dedicated maternal care. This article details the timing of reproduction, the development of the young, and the nesting behaviors that guide them toward independence.
Breeding Seasons and Frequency
Eastern Gray squirrels typically participate in two distinct breeding periods throughout the year. The first mating season occurs in late winter, usually spanning from December to February, resulting in a spring litter. A second breeding period follows in mid-summer, typically around May to June, leading to a late-summer or early-fall litter.
The gestation period for a female squirrel lasts approximately 40 to 45 days. Females generally produce one litter per year, but older mothers, particularly in years with abundant food, may successfully bear two litters. The average litter size is small, with females giving birth to between two and four kits, although litters of up to eight have been documented.
The Early Life and Development of Kits
Newborn squirrels, or kits, are categorized as altricial young. At birth, they are completely naked, their eyes are sealed shut, and they weigh a mere 0.5 to 0.65 ounces. The kits are completely dependent on their mother for warmth, nourishment, and protection during their initial weeks of life.
The first physical change occurs around one to two weeks postpartum when their skin begins to darken, and a fine layer of fuzz-like hair starts to appear. Their development accelerates; the lower incisor teeth typically erupt around three weeks of age. A milestone is reached between four and five weeks, when the kits’ eyes open, allowing them to perceive their surroundings.
By six or seven weeks old, the young squirrels have developed a full coat of fur, and their tails are beginning to look bushy. This is also the period when the mother begins to introduce them to solid foods, supplementing the nursing process. The kits remain dependent on the safety of the nest for survival during this developmental phase.
Nesting Behavior and Independence
The mother squirrel provides parental care, raising her young alone within a nest structure. These nests are either a drey, a bulky, spherical nest built from leaves and twigs high in the tree canopy, or a den located within a natural tree cavity or an abandoned woodpecker hole. The mother often lines the natal nest with soft materials for insulation and comfort.
She nurses her kits for approximately eight to ten weeks before the weaning process is complete. The nutritional richness of the milk supports the kits’ growth and development during this time. Once the young are fully weaned, the mother’s maternal care begins to wane.
The young squirrels start venturing out of the nest to explore and forage for food around ten to twelve weeks of age. This marks the beginning of their independence, as they soon disperse and establish their own territories. While males may reach sexual maturity around their first birthday, females typically become reproductively active at about 15 months of age.