Predators are most likely to catch weak, injured, old or very young prey. The strongest prey live to reproduce. When predators are removed, prey populations may grow unchecked until they eat all their own food and begin to starve. For example, where humans do not replace wolves and mountain lions as predators on deer, deer populations may grow beyond the resources of t heir environment. When that happens, deer starve during the winter or get hit by cars as they move outside their normal range in search of food.
Large sharks are the wolves and mountain lions of the sea.
In some places they may help keep ocean food chains in balance. Sharks in Danger Sharks have been around for about 400 million years. They have survived the mass extinction that marked the end of the dinosaurs and have competed successfully against similar predators such as the ichthyosaurs. For many thousands of years they have su rvived with humans. We have always used sharks.