Killer whales are known for their voracious appetites. In the ocean, their diet varies greatly. In fact, there is very little that the killer whale will not eat. They prey on fish, sharks, squid, birds and turtles. They are the only type of whale to eat other warm-blooded mammals. They eat dolphins, sea lions, seals, otters and walruses. They even sometimes attack large baleen whales such as the blue and the humpback. In their search for food killer whales may travel up to 120 km (75 miles) in a day. Killer whales receive all their fluids from the fish they consume as they live in a salt-water environment and are, therefore, unable to "drink" the water.

At Marineland, killer whales are fed a diet of herring and capelin, which is supplemented with daily multivitamins. Large killer whales may eat up to 113 kg (250 lbs) each day. This will vary depending on the age, weight, water temperature and type of fish being fed.

Calves are usually born fluke first as opposed to land animals which are more often born head first. The birth of a calf occurs rapidly, which is necessary because the young must surface for its first breath very soon after the umbilical cord breaks, otherwise it would die of anoxia. When the whale is ready to give birth, it sometimes is seen spiraling under the water's surface working with the force of water and gravity to expel the calf. A new baby weighs approximately 70 kg (150 lbs) and measures 2 m (6 feet) long. The mother quickly guides the newborn to its first breath of air and swims alongside her calf protecting it from intruders and danger. The mother is extremely protective of her calf. Nursing begins shortly after birth and continues for about one year. After approximately 2-1/2 months, the nursing periods become shorter and the calf starts receiving solid fish from its mother to supplement the milk received while nursing.