Arising over 350 million years ago, the shark species has been labeled as a human devourer. Now, with the increase in human population, the demand for shark meat, fins, and cartilage are at an all time high; therefore, the existence of the shark is becoming a concern (Budker 1971). Individuals are conditioned to think of sharks as a negative aspect to the environment, which is prolonging the effort to save shark species from becoming extinct. With that in mind, some private as well as national organizations have accepted the challenge of educating and informing people about the existence of the shark specie and its importance to the sea.
Portrayed as the beast of the sea, the shark species is a cold blooded animal that shows great diversity in size.
The largest of the sharks measure up to 13.7 m, while the smallest of the species range from 22-to-25 cm (Ellis 1976). Typically, these creatures of the sea have a fusiform body, that is composed of cartilage, which is capable of reducing drag and the amount of energy needed to swim (Ellis 1976). Their countershade coloration allows the species to blend in with both the dark depths and the light surfaces of the sea (Ellis 1976). These beautiful dwellers of the sea also possess rigid fins that are supported by cartilaginous rods. All together the shark has five different types of fins: the paired pectoral fins, are used to lift the shark as it swims, the paired pelvic fins stabilize the shark, the one or two dorsal fins also stabilize the shark, a single anal fin provides stability in species where it is present, however not all sharks have the anal fin, and the caudal fin which propels the shark (Lineaweaver and Backus 1970).
The sharks head structure consist of lateral eyes, a ventral external nose, and a mouth that is ventrally located at the tip of the snout. Some species possess an eyelid like structure called a nictitating membrane, which helps in protecting the eye from being injured when prey are thrashing around, and a nasal barber, which are sensory projections near the nasal (Lineaweaver and Backus 1970). In the mouth, teeth are modified, enlarged placoid scales. Having numerous rows of teeth attached at their bases by connective tissue, sharks have rows of replacement teeth that are continually developed behind the outer row. As the functional teeth fall out, the replacement teeth will take their place, and in some species as many as 30,000 teeth are replaced within a lifetime (Lineaweaver & Backus 1970).
Shark mating rituals vary from the size of the shark and its specie.
In smaller, more flexible species, the male coils around the female, while the male of the larger specie orients himself parallel and head-to-head with the female (Woums & Demski 1993). Some species mating rituals also consists of males biting females on the pectoral fins or the middle of the back to hold on to them (Woums & Demski 1993). The female will often bear scars or marks, after the ordeal. Due to the fact that sharks are cold blooded animals, there is no precise gestation time. The development of the embryo will depend solely on the temperature of the water, however, the gestation period can last anywhere from 2 months to 2 years (Woums & Demski 1993). Within shark species there are two methods of reproduction.
In some cases a female shark will lay eggs in a coastal nursery where the presence of other sharks are absent. And in other cases, usually in the larger sharks, females give birth to live offspring (Wourms & Demski 1993). In which case the young are born fully developed, and once they are born they shoot away fast or they risk being eaten.
Adapted for a wide range of aquatic habitats, various shark species inhabit shallow coastal habitats, deep-water ocean floor habitats, and the open ocean. With a wide selection to feed off of, as a whole the shark species feed on just about everything. Their diet consists of fish, crustaceans, molluscs, marine mammals, and other sharks.
When preying for their daily bread, the shark will seek out the weak, ill, injured or dying prey because it is .