Reproduction Reproduction A. Sexual maturity.
Most male walruses are sexually mature at about eight to ten years.
Successful reproduction, however, probably doesn't occur until 15 years of age, when the male attains full physical growth and is able to compete for females. Most females are sexually mature at about five to six years. Successful reproduction probably begins at about ten years. B. Mating activity. Only a portion of the female population mates each year, as some are pregnant from the year before.