Squirrels are common rodents found in parks and forests across the globe. They belong to the class Mammalia, and the answer to whether squirrels give live birth is definitively yes. Like nearly all other mammals, the reproductive process involves internal development of the young followed by birth.
The Direct Answer: Squirrels are Viviparous Mammals
Squirrels are classified as viviparous, a term that describes animals whose embryos develop inside the mother’s body and receive nourishment directly from her until they are born. This process is distinct from oviparity, where offspring develop inside an egg laid outside the parent’s body. Viviparity is a defining characteristic of almost all mammals, including all species of tree, ground, and flying squirrels.
The developing young are nourished through a specialized organ called the placenta, which facilitates the exchange of nutrients and oxygen. Squirrels undergo a period of gestation, where the embryo matures internally before the female gives birth to live young.
The Breeding Cycle and Gestation Period
The timing of births is closely tied to the availability of food and favorable weather conditions. Many squirrel species, such as the common gray squirrel, typically have two breeding seasons annually in temperate climates. The first mating occurs in mid-to-late winter, leading to spring births, while a second round in early summer results in late summer or early fall litters.
Following fertilization, the gestation period is relatively short, usually lasting between 40 and 45 days. The female gives birth to a litter commonly consisting of two to four young, though litters can range from one up to nine kits. The male plays no part in the rearing of the young after mating.
Postnatal Development and Care of Young Squirrels
Newborn squirrels, often called kits, are born in a state known as altricial, meaning they are undeveloped and completely helpless. At birth, the kits are blind, hairless, and have their ears closed, weighing only about half an ounce. They are unable to regulate their own body temperature and rely entirely on the mother for warmth, protection, and nourishment within the nest, known as a drey.
The young remain confined to the drey as they undergo rapid development over the next several weeks. Fur begins to grow, and their eyes typically open around four to six weeks after birth. At about seven weeks old, the kits begin to venture outside the nest for the first time, following their mother.
Weaning, the transition from mother’s milk to solid foods, occurs around 10 to 12 weeks of age. Once weaned, the young squirrels start to gain independence, but they may remain near their mother for a few more weeks to learn essential foraging and survival skills. By the time they are approximately four months old, most young squirrels disperse to establish their own territory and nest.