Great White Shark's Diet
The great white shark, perhaps one of the most feared animals in the ocean, has a diet comprising a number of other ocean animals. Great white sharks can reach a length of over 20 feet and weigh upwards of 4,000 pounds. Because they are known to swim up to 10,000 miles per year, great white sharks have to obtain a lot of energy through their prey.
Other People Are Reading
-
Marine Mammals
-
The great white shark's preferred diet consists of marine mammals such as seals, sea lions, dolphins and whales. These mammals are large and fatty, and because fat has twice as many calories per pound as protein does, sharks can get a lot of energy from eating fatty marine mammals. In fact, 65 pounds of whale blubber is enough to sustain a shark for about 45 days. Because of the benefits of eating marine mammals, great white sharks are known to intentionally visit offshore islands every winter to hunt the young seals that live there.
Fish
-
Great white sharks commonly eat other sharks, rays and smaller fish. Although small fish are not rich in calories, they are much easier to catch and are available nearly anywhere in the ocean. Researchers have observed sharks targeting the slower fish swimming at the edges of the schools and observe that predators such as sharks may aid in natural selection of fish within a species.
-
Hunting Behaviors
-
The most commonly observed way that sharks hunt large prey such as seals and sea lions is to swim just below the surface of the water and when directly below the prey to quickly thrust the head up out of the water, biting the animal on the way. Sharks also may quickly swim partially above the surface of the water when attacking prey, or even attack by swimming a long distance straight up from below the prey to avoid being seen.
Significance
-
As the animals at the top of many ocean food chains, great white sharks play an important role in the balance of the ocean ecosystem. Researchers at Stanford have found that there are only about 3,500 great white sharks left in the world, making the great white shark more endangered than tigers. The decline in the number of great white sharks may be a signal of a reduction in the amount of prey available to sustain them. Another possibility is that the shark's decline is due to other factors, and that the populations of its prey may grow excessively large as a result.
Shark Attacks
-
Contrary to popular belief, humans are not part of a great white shark's diet. Although sharks do sometimes attack humans, they do not end up eating the humans. Some scientists believe that shark attacks on humans are due to the shark's confusion, because humans can sometimes look like animals that a shark does eat. Most notably, when viewed from below, a person on a surfboard can look like a seal or sea lion, both of which are part of a shark's diet. Another theory is that hungry sharks may attack humans as a way to determine whether they are worth eating.
-
References
- Photo Credit white tip reef shark image by Wong Kim Fung from Fotolia.com
