Home / 英国北爱尔兰ASSIGNMENT代写:脊椎动物



The Greenland shark is a top predator that feeds on fish. However, hunting has never been observed. Clearing reports is common. Sharks replenish their diet with reindeer, moose, horses, polar bears and seals. Although sharks feed on seals, researchers are still unclear how it kills them. Because it lives in cold water, the metabolic rate of Greenland sharks is extremely low. In fact, its metabolic rate is so low that the species swims at the same speed as any fish, so it can’t swim fast enough to capture seals. Scientists assume that sharks may catch seals while they sleep. Low metabolic rates also cause slow and longevity in animals. Because sharks have cartilage defects rather than bones, dating their age requires a special technique. In a 2016 study, scientists performed radiocarbon dating on crystals in the crystals of captured shark eyes. The oldest animal in the study is estimated to be 392 years old, plus or minus 120 years. From these data, Greenland sharks have a life span of at least 300 to 500 years, making them the longest-lived vertebrates in the world.