
What Do Whales Eat? And Other Foodie Trivia
- Behavior
- Species conservation
- Natural history
- Sustainable seafood
You already know marine mammals are majestic creatures, but how well do you know their diets? Put your knowledge to the test.
Click “Show More+” to reveal the answer and more foodie facts. Plus, find ways to protect the marine food web and ensure a healthy ocean by supporting sustainable seafood.

What do whales eat?
Whales eat a variety of marine animals, ranging from tiny krill (shrimp-like crustaceans) to fish and even other mammals. A whale’s diet can depend on their species, environment and whether they have teeth or baleen along their jaw.
Baleen whales, such as humpback and blue whales, have hundreds of rows of bristly baleen plates instead of teeth. Most baleen whales eat by taking a large mouthful of food and water, and then straining the water through the gaps in their baleen. Prey like small fish and krill get trapped on the inside edge of the baleen. Even though baleen whales eat very small creatures that are low on the food chain, these whales are all very large and eat great quantities at once.
Toothed whales, such as porpoises, dolphins and sperm whales, have teeth, as their name suggests. They can use echolocation or sonar to detect objects in their environment, including food, and can grab fish and other prey using their teeth.
In recent years, increasing numbers of large whales, dolphins and harbor porpoises have been utilizing the San Francisco Bay as habitat and new feeding grounds. Unfortunately, they can encounter ships in the area as they enter high-traffic routes, creating the potential for fatal collisions. The Center’s researchers are conducting scientific studies to monitor these animals and find solutions.
What do seals and sea lions eat?
Seals and sea lions are carnivores that may eat marine animals like fish, squid and octopus in the wild. Their diets vary from species to species, but most seals and sea lions are opportunistic feeders, which means they hunt for a range of prey depending on what is available in their habitat.
When seals and sea lions are admitted to our hospital for life-saving care, our veterinary experts determine personalized treatment and feeding plans that include lots of nutritious, sustainably caught herring. Many of our young patients don’t even know that fish is food, so specially trained volunteers help them learn vital skills to feed themselves. Lessons in fish school include tactics like dragging fish on a string through the water to engage a pup’s natural instinct to catch fish. Once our patients receive a clean bill of health and can show our experts they have the hunting skills to survive in the wild, they are released to their ocean home with a second chance at life.


What do sea otters eat?
As one of the few animals that use tools, sea otters mostly feed on shelled creatures like urchins, crabs, clams and abalone, using a rock to break them open. Sea otters eat about a quarter of their body weight every day!
Did you know that a sea otter’s diet helps fight climate change? Sea otters are a keystone species, which means they are essential to maintaining a healthy ecosystem. As top predators, they help control populations of purple sea urchins—which are voracious kelp grazers—so that kelp forests can flourish. And not only do these thriving kelp forests provide habitat to other species, but they’re also very efficient in capturing carbon dioxide, which strengthens our natural defenses against climate change.
With only about 3,000 southern sea otters left in the wild, each individual otter is essential to saving this threatened species. As one of the few organizations permitted to rehabilitate southern sea otters, the Center has provided many animals with a second chance at life and expanded overall knowledge of threats sea otters face, which informs how we can better protect this population.
People and marine mammals are interconnected. We need a healthy ocean to thrive and rely on seafood as a source of protein. But with increased fishing pressure and diminishing fish populations, the entire marine food web is changing. The ways people catch fish will continue threatening populations and damaging habitats if we don’t take action.
Your seafood choices matter for a healthy ocean. By supporting sustainable fisheries and aquaculture, you can help ensure there are plenty of fish for marine mammals and people for generations to come. Explore ways you can choose sustainable seafood to protect our shared ocean.
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Read Morespecies conservation
natural history
sustainable seafood