When Do Squirrels Have Babies?: Breeding Timeline
The Eastern Grey Squirrel (Sciurus Carolinensis) is what we typically see in Ontario. While called the Eastern Grey squirrel, it actually isn't necessarily grey coloured but can appear black, grey, or brindle. There is a theory that the darker the squirrel, the better equipped for cold climates it is - that black coloured Eastern Grey squirrels have a geneting mutation that allows for better adaptation to low temperatures.
In contrast to the lesser present Red Squirrel, these agile and entertaining acrobats have generally two breeding seasons. Join us as we explore the factors influencing the reproductive cycles of squirrels!
Squirrel Breeding Season: When Do Squirrels Have Babies?
In Ontario, squirrel babies are born in spring and often again, in the fall season. First time squirrel mothers will often have just one litter in their first year of sexual maturity. Scent plays a large role in squirrel mating and breeding rituals. No, famale squirrels will not spritz the Chanel No 5 kind of scent, but rather mark their territory and signal their ability and willingness to mate. In turn, nearby males will then evalulate the information gathered from the scent left for them and pursue the lady of their choice, with the strongest, most dominant, and often older males having a bit of an advantage. The courting ritual consists of a noisy mating chase by one or more males pursuing the female through the trees. Ms Squirrel, however, is the one in charge here. SHE will determine who gets the privilege of being her baby daddy. Both male and female squirrels may have multiple partners in one breeding season, although the first male to mate with a female is usually the one to impregnate her. He will leave a waxy plug in her vagina and thus blocking other male's sperm.
Spring Breeding
Spring squirrel mating and breeding season kicks into high gear between December and January and extending into February, depending on the severity of the winter and availability of food. Momma will give birth to her squirrel kits after a roughly 44 day getstation period to one to six wee ones, with older and more experienced females having larger litters. Squirrel nesting behavior means that her little ones will stay with her in the nest exclusively for at least six weeks (that's why you generally won't see very small squirrels in your yard) and then set out on their own after mum deems their survival training complete. This frees mum up to consider one more litter.
Fall Breeding
If not first time/season moms, Eastern Grey squirrels will often breed again between June and August, with the fall litter usually arriving late summer or early fall. These little ones will be ready to leave home and explore the world on their own just before winter. Mum will have taught them the art of nest building, but they may also choose to renovate an existing abanoned nest. Red squirrels will sit this one out; they only breed once in the spring.
Factors Influencing Squirrel Breeding
It makes sense that newborn squirrels aren't arriving in the midst of winter. As with all species, little ones need warmth and mum has to be able to feed herself while nursing, and then her offspring. Squirrels do not hibernate and are active throughout the winter. They are master architects when it comes to nest building. both for child rearing and to survive our harsh winters - learn more about squirrel nests and dreys »
Seasonality
The spring breeding is the one shared by all squirrels, although the mating actually takes place while winter is still in full swing. The fall (or late summer) squirrel breeding season observed by the Eastern Greay squirrel seems to be much more in line with sumer fun and frolicking in the sunset :)
Read more: When Do Squirrels Have Babies?: Breeding Timeline