Reproduction

When in estrus, the female's scent changes subtly and nearby males begin pursuit.[37] In addition, a female alerts males she is in estrus by whistling through her nose.[29] During mating, the female has the advantage and mating choice. Capybaras mate only in water, and if a female does not want to mate with a certain male, she either submerges or leaves the water.[29][34] Dominant males are highly protective of the females, but they usually cannot prevent some of the subordinates from copulating.[37] The larger the group, the harder it is for the male to watch all the females. Dominant males secure significantly more matings than each subordinate, but subordinate males, as a class, are responsible for more matings than each dominant male.[37] The lifespan of the capybara's sperm is longer than that of other rodents.[38] Capybara gestation is 130–150 days, and produces a litter of four young on average, but may produce between one and eight in a single litter.[7] Birth is on land and the female rejoins the group within a few hours of delivering the newborn capybaras, which join the group as soon as they are mobile. Within a week, the young can eat grass, but continue to suckle—from any female in the group—until weaned around 16 weeks. The young form a group within the main group.[19] Alloparenting has been observed in this species.[34] Breeding peaks between April and May in Venezuela and between October and November in Mato Grosso, Brazil.[7]