Newborn pups usually measure 114–160 cm (3.74–5.25 ft) long and weigh 5–6 kg (11–13 lb), depending on the size of the mother. The juveniles grow about 50 cm (1.6 ft) a year, while adults grow about 10 cm (0.33 ft) a year.[15] The size at maturation appears to vary between populations. In the eastern North Pacific, males mature at 3.3 m (11 ft) and five years old, and females around 2.6–4.5 m (8.5–14.8 ft) and seven years old.