Two calving peaks occur in the eastern tropical Pacific, one in spring and one in fall (Jefferson et al. 1993). Calving interval averages 2-3 years in eastern Pacific, 4-6 years in western Pacific. Males are sexually mature at average age of 15 years, females at average of 10-12 years. Old females may not reproduce. Maximum longevity may exceed 45 years (see Perrin et al. 1987).