The shark is classified as a fish. However, it differs from other fish in significant ways. Different species vary considerably from each other as well. A sharks life cycle is different from shark species to other shark species too.
Fish have bones supporting their bodies. Sharks have cartilage which is much softer and does not offer as much support. The shark cannot live out of water for more than a few minutes. This is a major difference between sharks and fish.
Although the shark is considered to be unintelligent, it has managed to exist for 300 million years. The sharks life cycle is dependent on the type. One species will live for 20 to 30 years on average.
The Piked Dogfish is an extreme exception. It lives from between 70 and 100 years. Sharks have three ways of giving birth. It varies from species to species. Some lay eggs and swim away as other fish do. Some will lay their eggs and carry them until they hatch. Still others carry them within their bodies and nourish them through an umbilical cord, just as warm blooded mammals do.
The time required for gestation is from 9 to 22 months. The female produces from one to 100 eggs or pups at one time. Humans everywhere can envy one fact about sharks. They are able to replace their teeth as they wear out. New teeth come in throughout the entire life of the shark.
The name for a young shark is the pup. One of the most widely studied of these creatures is the lemon shark. It resides in relatively shallow water and is territorial, thus available to be analyzed over a lifetime. It is found to mature after 13 to 15 years of life.
For the first three years of life, the lemon shark pup stays within a territory the size of 11 football fields in the warm, murky waters near Bimini. As they grow, their habitat expands with each year of life. They hunt for food in increasingly larger areas.
When sexual maturity is attained (13 years for the male and 14 to 16 for the female), they will be living and hunting in about a sixteen mile area. At that age they are seven feet long. The sharks life cycle encompasses about 25 years altogether.
In his studies of sharks one feature that has always fascinated Richard Williams is the sharks life cycle.
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