Squirrels pregnancy lasts 35-38 days, in litter from 3 to 10 cubs; in the second litter less. Newborns are whitish, naked and blind, weighing about 8 g.
Squirrels are very prolific. On most of the range, 1-2 litters are brought, in the southern regions – up to 3 litters. The Yakut squirrel usually has only 1 brood per year. The breeding season, depending on latitude, feed conditions and population density, begins in late January-early March and ends in July-August.
During the race around the female, 3-6 males are holding, which demonstrate aggression towards their competitors – loudly growling, pawing on branches, running after each other. After mating with the winner, the female builds a brood nest (sometimes 2-3); it is neater and larger.
Their hair cover appears on day 14, they only see 30-32 days. From this moment they start to leave the nest. Milk is fed up to 40-50 days. At the age of 8-10 weeks leave the mother. Sexual maturity is reached in 9-12 months. Having grown the first litter, the female is somewhat fattened and mated again. The interval between broods is about 13 weeks.
