They are one of the few individuals that survived themselves from being extinct. Many think that shark is cruel in nature but the fact is that there are only few out of 350 species of sharks that are considered dangerous: the great white shark, tiger shark, bull shark and oceanic white tip shark.
They can survive in all the weather conditions from cold to temperate waters. They are also found in water bodies with temperatures around 90 degrees Fahrenheit. Almost all sharks are carnivores and eat seals, dolphins, sharks and other fish. They are classified into cold-blooded animals. This means that their bodies change temperature as the water temperature changes. Sharks have a body structure of sleek, streamlined design which supports them to swim without using up a lot of energy. This is very important because they don’t sleep and most of them continue their journey without sleeping.
God always provide every creature an ability to defend itself from enemies and so sharks have skin like the spiky suit of armor. Just as the teeth in their jaws are replaced after certain period of time and same as spiky teeth on their body are also changed. Throughout the life the sharks have supply of teeth. In a year an adult shark goes through 7 to 12 sets of teeth. In order to satisfy their needs different species of sharks have different types of teeth. Sharks do not make use of their teeth to chew. They gulp down things whole or in big pieces. The most common shape of teeth of sharks is plate-like triangular one.
They are provided with six senses which make them very well equipped to have their prey. The six senses which shark use very effectively for searching and hunting their prey are vision, vibration, hearing, smell, taste and electro-perception. A shark with its ampullae’s can sense vibrations in the water and will fly through the water straight to the source. Shark has very sensitive nostrils and can find its prey even of small size with great accuracy. They rest during the day time and go for their hunt at the evening and dark hours. As per survey in a zoological environment they eat about 1 % to 10% of its total body weight per week.
Mating of Sharks
The mating actions change as per their size. In smaller species the male curls around the female. In larger species the male arranges himself parallel and in line with the female. Males of many species during mating bite females on the pectoral fins or the middle of the back to hold onto them. Females often bear wound or marks after mating. A close look at these marks shows that they have been made by upper jaw teeth. In some blue shark female sharks, the skin on the back and flanks is double as compared to those of males. Fertilization of Shark and batoid eggs takes place within their body. For energy-intensive reproduction, internal fertilization is a key adaptation. After the birth young sharks are fully formed and physically able to survive themselves. The number of sharks found in a group usually does not go beyond 100 since the sharks can survive on their own even when they are very young. Clasper is the name given for modified inner edges of the pelvic fins of male sharks. While mating, the straight claspers are bent forward. The male puts in one clasper at a time into the female. The muscles cause seminal fluid down a groove in the clasper and into the female oviduct.
At a time depending on its species, sharks have from 1 to 100 pups. Some sharks lay eggs while other give birth to live pups. Some sharks do not worry about their pups after they are born, although they will search out safe places, where they can lay eggs or give birth. Many pups swim near to shore to grow up on their own. They require 10 to 15 years to grow fully and have an average life span of 100 years.
More time humans spent in their world, the more trouble is cause to them. Human beings should not interfere in their world doing so causes harm to both. A shark is the creativity of God and we should respect their power.
http://www.buzzle.com/editorials/8-9-2004-57651.asp
by: : http://www.buzzle.com/authors.asp?author=949
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