* Plankton: Plankton are microscopic organisms that drift in the ocean. They are a food source for many small fish, which in turn are eaten by whales.
* Cephalopods: Cephalopods are a group of invertebrates that includes squid, octopus, and cuttlefish. They are a food source for many toothed whales, such as the sperm whale, orca, and bottlenose dolphin.
* Fish: Fish are a food source for many whales, both toothed and baleen. Some whales, such as the killer whale, specialize in hunting fish.
* Marine mammals: Some whales, such as the orca, also eat other marine mammals, such as seals, sea lions, and porpoises.