A calf swims alongside a mature orca. There are actually 3 different types of orca groups (pods). One, a resident orca eats only fish. The second, a transient orca eats most marine animals (including seals and other whales) and the offshore pod which eats both types. Scientists believe that once an orca is raised in a certain kind of pod, it will never eat anything other than what it was taught as part of it's pod.