Squirrels are a familiar sight in many neighborhoods, often observed foraging, climbing trees, and building their nests. While their daily activities are visible, the intricate details of their reproductive lives, particularly pregnancy, often remain unseen. Understanding these aspects offers insight into the life cycle of these rodents.
Squirrel Pregnancy Duration
The duration of a squirrel’s pregnancy, known as the gestation period, varies slightly depending on the species. For common grey squirrels, the gestation period typically ranges from 40 to 45 days. Red squirrels generally have a shorter gestation, often cited as 36 to 40 days.
Across different squirrel species, the overall gestation period usually falls within a range of 30 to 46 days.
Breeding Cycles and Pregnancy Signs
Squirrels commonly undergo two breeding cycles annually, leading to litters born in different seasons. The first breeding season typically occurs from late December or January, extending into February or early spring. A second breeding period often takes place from May or June through August, resulting in late summer or early fall litters. Red squirrels, however, might only have one breeding period, typically in late winter or early spring.
Female squirrels are polyoestrous, meaning they have multiple ovulation cycles each year, yet they are receptive for mating only for a single day during each cycle. Observable signs indicating a squirrel’s pregnancy include increased nest building, as the female prepares a sturdy natal drey for her young. Pregnant squirrels also tend to have an increased appetite, and their abdomen may appear larger and distended.
Newborn Squirrels and Early Development
After the gestation period, newborn squirrels, often referred to as kittens, pups, or kits, are born in an altricial state. They are blind, deaf, and hairless, completely dependent on their mother for survival. At birth, grey squirrel kits typically weigh between 14 and 18 grams, while red squirrel kits weigh around 10 to 18 grams. They are also quite small, usually around an inch in length.
The development of young squirrels is rapid, with fine fur beginning to appear around two weeks of age and a full coat developing by three to five weeks. Their eyes typically open between four and five weeks (28 to 35 days), and their ears also become functional around four weeks. Kits start to venture out of the drey at six to eight weeks of age and begin to sample solid food around six to seven weeks. Weaning from their mother’s milk usually occurs between eight and twelve weeks, and young squirrels become independent around 10 to 12 weeks of age, though some may stay with their mother longer. The mother squirrel provides consistent nursing and protection throughout this early developmental phase, sometimes even moving her litter to an alternative drey if disturbed.