Epidemiologists study outbreaks of diseases, the causes, locations, and how various communities are affected, utilizing relative information to aid in the prevention of future outbreaks. Epidemiologists help to keep the public informed of methods to maintain and improve public health.
Based on these criteria, the smallest known extant shark species appears to be Etmopterus perryi, males of which mature at 16 to 17.5 cm TL and gravid females have been found at 19 to 20 cm TL (Springer & Burgess 1985).
Today, the largest shark roaming the oceans is the huge whale shark. Unlike the megalodon, whale sharks are not predators. Instead, they're slow-swimming giants that eat mainly plants and plankton. Although not the size of the megalodon, whale sharks are still really big. They can grow to be over 40 feet long and weigh over 15 tons, which makes them the largest fish in the world.