A Very Brief Look At A Sharks Life Cycle
A sharks life cycle is very interesting. We don’t really know that much about their life cycle because man has not been able to study many of the mating, birth, and lives of the over four hundred species of sharks that populate the world.
The few sharks that have survived in captivity and have been studied are where most of the “averages” that you read about come from. These are a fraction of the vast number of sharks that cannot be captured, held in captivity, or studied successfully in the wild.
The gestation period of a shark can last from 9 months to two years. The three methods for birth are the ovoparity in which eggs are laid in a crevice or crack in a protected area. The egg is a tough leather-like casing that is screwed into the crevice or crack so that it is hard for predators to retrieve.
Some sharks carry their eggs in the womb, called the ovoviparity method. When a pup hatches from the egg it feeds on the other eggs in the womb and the fluids, then is born fully developed and functioning. The viviparity method is the same as mammals. The pups are carried in a placenta, nurse and are weaned there and then are born and swim away from the mother.
A reason that there are over eight species of shark are threatened with extinction is because there is no regulations to protect them. Sharks are not like other fish that lay a lot of eggs and have several hundred babies every few months. Some sharks do not reach maturity until they are in their teens and have one or two pups every two years. With 30-100 million sharks being killed each year, there is not enough time for the shark population to recover.
On average, a shark lives up to twenty-five years. But, remember that there are no real statistics on sharks that we have not been able to study. No one knows for sure how long a Great White lives. A Great White that is being followed in the wild is currently 25 years old. There are Whale Sharks living that are thought to be at least 100 years old.
Studying sharks has always Seiji Tadashi’s passion for as long as he can remember and has always pondered about the sharks life cycle.
Tags: Animalia, animals, Animals and Plants, Biology, Cartilaginous, Chordata, Fish, Flora and Fauna, outdoors, recreation, Science, sharks, Zoology