Reproduction

Mating occurs more often among killer whales of different pods to avoid inbreeding within pods. About 16 to 18 months after mating, females give birth to a single calf. Newborn calves weigh about 200 kg (440 lb) and are about 2.5 m (8 ft) long. Mothers nurse their calf for 14 to 18 months, although mothers continue to be protective of their young long after the offspring have been weaned. On average a female orca has from 3 to 5 offspring during a reproductive lifetime of about 25 years. She might have her first baby around 14 years of age, although we know of younger females who have become mothers as early as 10 years of age. Babies are often born between October and March. Scientists do not know how long killer whales live in the wild. Scientists estimate that male killer whales in the Pacific Northwest have an average life span of about 30 years, while females can live up to 60 years.