Killer whales live in tight-knit families or pods, which are matriarchal family groups. Animals born into a pod stay in the pod their entire lives. Each matriline often contains three or more generations. The head female or matriarch leads the pod, as orcas are a female dominated species. The matriarch tends to be the oldest female in the extended family. Her experience and knowledge guides the pod, and the matriarch teaches younger dolphins about everything from parenting skills, feeding tactics, and navigation through the vast territories that they cover.
Orcas have long life expectancies, 60 to 80 years for females and 40-60 years for the males. Females have the ability to reproduce as early as 14 years of age, but it is more common to see a female first calf at around 17 to 18 years old. Males reach sexual maturity between the ages of 17 and 20, but DNA research has revealed that older males are more successful. An orca gestation period averages 16 to 18 months.