Reproduction in Pteronura brasiliensis is documented primarily by observations done in captivity. Peak breeding season begins in late spring and early summer, although some breeding takes place throughout the year. Females are receptive for 3-10 days of the 21 day estrous cycle. Swelling of the nipples and vulva signal receptivity. Mating occurs in the water. After fertilization, gestation ensues for 65-70 days. Birth of altricial young occurs in late August through early October.
High juvenile mortality often leads to conception of a second litter of offspring, born from December to April. Litter size ranges from 1-5 individuals (usually 2-3), each weighing approximately 170-230g. Cubs are kept in family dens for the first 2-3 weeks of life. Offspring open their eyes at 1 month and begin to regularly follow parents out of the family den. Young P. brasiliensis are weaned 3-4 months after birth. They are independent hunters and indistinguishable from their parents at 9-10 months. Sexual maturity of P. brasiliensis is reached at 2 years.
The estimated lifetime of P. brasiliensis is 10-13 years.
Carter and Rosas (1997), Gittleman (1989) , Macdonald (1984), Nowak (1991), Parker (1990), Redford and Eisenberg (1992)
Average birth mass: 204.25 g.
Average gestation period: 68 days.
Average number of offspring: 1.5.
Average age at sexual or reproductive maturity (female)
Sex: female: 730 days.