As a killer whale ages it makes growth layers of dental material. The calves grow 2.6 feet in their first year and 2.2 feet in their second year. Killer whale calves start eating fish when they are 3-4 months old. Overall the favorite foods of a killer whale are mackeral, herring, squid and salmon. What an orca whale eats partially depends on whether it is a resident whale or a transient whale.
Resident whales eat mainly fish but transient whales eat seals, penguins, and other whales.
Whales can go without eating for stretches and when food is scarce they live off their blubber. They rarely eat during mating season. Killer whales have to eat a lot because they need the food energy to stay warm.