Whale sharks, which are the largest fish that ever lived, are plankton feeders like the great whales, thus the name. The more than 350 species all differ in habitat, lifestyle and body form. Although there have been some reports of people being poisoned by shark meat, the meat from the majority of sharks is edible and delicious when properly handled and prepared. Sharks' relatively large and complex brains are comparable in size to those of supposedly more advanced animals like mammals and birds. Sharks also can be trained.
Most sharks prefer to eat certain types of invertebrates, fish and other animals.
Some sharks eat mainly fish. Others eat other sharks or marine mammals. Some sharks are even plankton-eaters. Most sharks don't appear to be especially interested in the blood of mammals as opposed to fish blood. Sharks eat periodically depending upon their metabolism and the availability of food.