Capybaras are polygynous to promiscuous. Dominant males in social groups try to monopolize mating activity, but this can be nearly impossible, especially in larger groups. Little research has been done on female mate choice in capybaras, but females have been observed mating with both dominant and subordinate males.
Mating System: polygynous ; polygynandrous (promiscuous) ; cooperative breeder
Capybaras breed throughout the year, with a peak in breeding activity at the beginning of the rainy season. When a female comes into estrus, a male will begin to follow her closely, sometimes for long periods of time, before mating occurs. During this time, the male is often driven off by a more dominant male, who then takes his place. Copulation occurs in the water and typically lasts only a few seconds, but a female usually copulates several times per estrus period. Young are born after 150 days, in litters ranging in size from 2 to 8.The young are precocial, beginning to stand and walk shortly after birth, and can graze within a week of being born. They are weaned at about 3 months old, during which time they suckle both from their own mother and the other females in the group, who are usually closely related.
Breeding interval: Capybaras produce one litter of young per year.
Breeding season: Breeding occurs year-round with a peak in May and June, the beginning of the rainy season.
Range number of offspring: 2 to 8.
Average number of offspring: 4.
Average gestation period: 150 days.
Average birth mass: 1.5 kg.
Average weaning age: 3 months.
Average time to independence: 1 years.
Average age at sexual or reproductive maturity (female): 18 months.
Average age at sexual or reproductive maturity (male): 18 months.
Key Reproductive Features: iteroparous ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); viviparous
Young capybaras stay with their parents' group until they are about a year old. They nurse for the first three months of this time. Both before and after weaning, the young move around together in a creche, and some of the work of parenting (such as suckling and watching for danger) is shared among all adults in the group. During much of their first year of life, the young are small, slow, and easily tired, making them especially vulnerable to predators. The protection of their natal group is essential to staying alive. Little is known about individual parental care in capybaras, but it seems that, because of the precocial state of the young and the system of cooperative parenting, the time and resources spent by each parent after birth are minimal.
Parental Investment: precocial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female); pre-weaning/fledging (Provisioning: Female, Protecting: Male, Female); pre-independence (Protecting: Male, Female)