Tiger sharks may have as many as eighty pups at one time, but many sharks have only a few pups every few years. Like lions or wolves, their counterparts on land, sharks prey on weak and sick animals, thus keeping fish and mammal populations at a healthy number. Recall that the majority of sharks, such as the cigar shark and reef sharks, are considered small at less than three feet in length. These small and medium sized sharks are not at the top of the food chain. Other sharks, larger fish and mammals can and do eat them.
Experts consider only half a dozen types of sharks to be very dangerous.
Most are shy and harmless, avoiding people and other large animals when possible. On the other hand, people kill over a hundred million sharks per year. Their rough skin and sharp teeth were once used for sandpaper and spears. Now their skin is used as a strong leather. Some sharks are eaten for their meat or in shark fin soup, while others are used for fertilizer or as food for livestock.