Sharks interact with a variety of different animals in their habitat, as they are predators, prey and hosts for a variety of other species. While some sharks reach large sizes and as adults are apex predators that fear no predators themselves, the majority of the world’s 400 living species of sharks are relatively small and thus serve as prey to other species.
Sharks prey on a wide variety of species. Small species of sharks, such as the spiny dogfish, primarily consume small crustaceans, such as crabs and lobsters. Medium-sized sharks eat crustaceans as well, but they also consume different types of fish and turtles. Great whites, the largest predatory shark species, consume large fish and hunt seals and other aquatic mammals. Basking sharks and whale sharks are the largest shark species on the planet, and they feed almost entirely on krill, small fish and microscopic organisms that they capture through filter feeding.
Small species of sharks must do their best to avoid larger sharks that attempt to eat them.The young of many shark species inhabit different areas of the ocean than adult sharks to avoid predators. Large fish, such as barracudas, often prey upon small sharks, and humans prey on sharks as well. According to the World Wildlife Fund, humans kill up to 100 million sharks each year.
In addition to being predators or prey of the species that live alongside them, many sharks serve as hosts for parasites. Shark suckers, which are also called remoras, are one example. Shark suckers attach themselves to sharks, and they live off of the scraps of food the sharks' feeding behavior generates.