Yellow-pine chipmunks are polygynandrous. Females are in estrous for one day each year. They use vocalizations to attract mates a few days before the onset of estrous. On the day of estrous, females are typically pursued by two to six males in what is called a “mating chase”. A female mates with multiple males during this mating chase. All sexually mature males and females mate during the mating season, which occurs in late April or early May.
Mating System: polygynandrous (promiscuous)
Female yellow-pine chipmunks are in estrous for one day and breed only once per year during late April to early May. Average gestation period is 30 days, after which a female usually gives birth to a litter of 3 to 8 babies. Young are highly altricial at birth and remain in the burrow until they are weaned at six weeks of age. Young begin to disperse and find their own burrows at about 8 to 12 weeks of age. They reach sexual maturity at 12 to 23 months.
Breeding interval: Yellow-pine chipmunks breed only once per year.
Breeding season: Breeding occurs in late April or early May.
Range number of offspring: 3 to 8.
Average number of offspring: 4 to 5.
Range gestation period: 28 to 40 days.
Average gestation period: 30 days.
Average weaning age: 45 days.
Range time to independence: 2 to 3 months.
Range age at sexual or reproductive maturity (female): 12 to 23 months.
Range age at sexual or reproductive maturity (male): 12 to 23 months.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization ; viviparous
Average birth mass: 2.62 g.
Average number of offspring: 5.19.
Pregnant females make nests of leaves, grass, lichen, and feathers in burrows that are about 1.5 m below ground or up to 18 m in trees. Babies are altricial and depend on the mother for food and protection until they emerge from the burrow at about 6 weeks of age. Males do not contribute to the care of the offspring. At about 8 weeks of age, young of both sexes disperse to find their own nests and burrows for winter.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Female); pre-independence (Provisioning: Female, Protecting: Female)