The narwhal, a medium-sized whale with a long tooth that looks like a unicorn's horn, feeds on fish that swim in Arctic seas such as Greenland halibut, arctic cod, polar cod, squid, shrimp and cuttlefish. Because narwhals do not have well-developed teeth, they swim close to their prey and suck it into their mouths.Continue Reading
Narwhals feed in deep Arctic waters often covered in sea ice, and for this reason it has been difficult to observe them feeding. Information on narwhal feeding habits has been obtained from examining their stomach contents. From these, it has been determined that they follow a very restricted and specific diet of only a few species of fish. Unlike most sub-arctic whales, narwhals feed mostly in winter. During the ice-free months of summer their stomachs are nearly empty. To feed, they make long, deep dives of up to 25 minutes into the total darkness at depths up to 4,500 feet. Physiological adaptations such as a compressible rib cage and the ability to carry a large amount of oxygen in their lungs, muscles and blood enable them to make the dives.
In medieval times, narwhal tusks were more valuable than gold, as they were believed to be unicorn horns. People attributed magical powers to them. In fact, the narwhal tusk is a front tooth that grows right through the narwhal's lip up to about 9 feet in length. Usually only males have tusks, and if females grow them, they are not as long as those of the males. Scientists have speculated about the purpose of the tusks, but the most prominent belief is that they have something to do with narwhal mating rituals.Learn more about Marine Life
A wide variety of fish, including cod, flounder and wolffish, eat young lobsters. Once lobsters reach maturity, however, they have few predators aside from man. An adult lobster is most vulnerable to predators when it is molting, as its movement is limited and its exterior is soft.Full Answer >
Dolphins eat a variety of fish depending on their species and location, with bottom-dwelling and schooling fish such as mackerel, hake and cod, being popular among ocean-dwelling species like the Atlantic white-sided dolphin. Dolphins of the River Ganges eat catfish, freshwater sharks, gobies and carp.Full Answer >
Seahorses are eaten by birds, crabs, fish and other sea creatures, but are not a preferred food by many predators because they are primarily made of bones and skin. In order to avoid being eaten, seahorses will change colors to match their surroundings, which helps them disappear and hide from any predators that are pursuing them.Full Answer >
Cnidarians obtain food, mostly prey animals such as crustaceans and fish, by passively waiting for animals to pass by and touch their tentacles, whereupon they poison them and draw them toward their mouths to be digested. One important exception to this pattern is corals, which instead have a mutualistic relationship with algae which generate food for them via photosynthesis. Cnidarians obtain food very passively, but also have low food requirements.Full Answer >