Whales are some of the largest marine mammals that live in all of the world's oceans. What do whales eat is a great question to start with for learning about the different kinds of whales since that is what puts them into their two suborders. There are two suborders; one for whales with teeth, and those who filter feed. Whales with teeth are known as toothed whales and their suborder is Odontoceti. Whales that filter feed are known as baleen whales (because the plates in their mouths that they use to eat are called baleen plates) and their suborder is Mysticeti.

A killer whale is an example of a toothed whale, and they are probably the most popular toothed whale on the planet. It is not uncommon to see these whales at sea world or other aquarium being fed fish. A blue whale is a type of filter feeding whale. Filter feeding whales have plates on their upper jaw that look like the teeth of a comb. These plates filter food from the ocean water. Both types of whales are usually classified as predators, although not all whales eat other large animals. Filter feeding whales feed on some very small creatures.

A killer whale is also known as an orca. They are one of the toothed whales and live in various oceans around the world. Their diets depend on which ocean they live in, which makes what do whales eat an especially important question when learning about these types of whales. Toothed whales survive by eating other animals. Some regions of killer whales eat mostly fish. However, some killer whales will also eat much larger prey such as rays, sharks, squid and even sea turtles. Another common prey for these whales is the seal and the sea lion. In order to avoid getting hurt while hunting these larger animals, killer whales will often try to stun their intended meal by slapping it with their tails or by jumping out of the water and landing on it. In smaller regions, killer whales have also been known to eat birds that land on or swim in the water. In a few rare cases, they have even been known to eat large land animals that venture out for a swim. Killer whales eat about 500 pounds of food each day.

Blue whales are the largest known animal on the planet. It is a filter feeding (or baleen) whale. Unlike the killer whale, the blue whales diet is simpler. They almost always eat only krill. Krill are small crustaceans. An adult blue whale can eat about 40 million (yes, million) krill each day. This can amount to about 7700 pounds of krill in one day. In order to find these large amounts of food, the blue whale must feed at depths of 330 feet, although they may feed closer to the surface at night. Once a blue whale has found a large group of krill to eat, they dive below the group of krill and swim quickly upward with its mouth wide open. This will get them both the krill and a large amount of water into its mouth. The water is then pushed through the comb like plates in the whale's mouth and the krill are left behind to be swallowed. Any other fish or squid that got caught with the krill are swallowed as well. Even though you wouldn't think so, the largest animal on the planet eats some of the smallest animals in order to live.

A What Do They Eat? project.