They also tend to stay in waters with surface temperatures ranging from about 10 C to 32 C, migrating seasonally, with a more southerly distribution in the winter. Females take 7 to 10 years to reach the full adult size, and males take about 12 years. Females can begin to have young at approximately age 5 to 12, and males can father young at age 10 to 13. Life spans of more than 40 years for males, and more than 50 years for females have been documented. They are carried by their mothers for about one year, and newborns average 3.5 feet long and a little more than 40 pounds.
Females can have a calf every two years, but average three years between births.
The mothers nurses young with a rich milk helps the baby rapidly develop a thick, insulating blubber layer. Calves can nurse for up to 18 months, and begin to switch to fish after their teeth have begun to grow in, but stay with their mothers for several years. Fish, squids, small crustaceans such as shrimp. Based on surveys and analyses of sighting data, the offshore population appears to be larger than the coastal population. There are indications that the inshore population may be declining.