Jellyfish are eaten by a variety of marine animals, including sea turtles, sunfish, sharks, and some species of birds. Some other cnidarians such as anemones, certain nudibranches, and different types of jellyfish also feed on jellyfish. Among the predators of the jellyfish, the following have been identified: ocean sunfish, grey triggerfish, turtles (especially the leatherback sea turtle), some seabirds (such as the fulmars), the whale shark, some crabs (such as the arrow and hermit crabs), and some whales (such as the humpbacks) . Some species of sea slugs are also able to eat jellyfish by ingesting only the nematocysts and not the rest of the tentacles. It is worth noting that jellyfish are considered to be opportunistic feeders, meaning they will consume whatever prey is available to them.