The type of food a whale eats, depends on what kind of whale it is. Toothed whales use their teeth to capture fish and squid. Some whales have been found with marks on their head, suggesting that some of their prey fights back. The most likely prey to fight back is the colossal squid. The Killer Whale is an aggressive predator and will often hunt down its prey in a pod (group of whales). They will circle, for example, another large whale, before attacking. All marine mammals are threatened by Killer Whales.

Baleen Whales strain zooplankton and small fish into their mouths from the water around them. A Blue Whale can eat up to 3,000 kg of krill and tiny fish in a day. Baleen whales tend to eat for 6 months of the year, in warmer waters and then spend the following months travelling and breeding. The excess energy gained from the feeding season is stored as blubber, which will sustain the whales when food is scarce.