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).
There are four basic types of shark teeth: dense flattened, needle-like, pointed lower with triangular upper, and non-functional. The type of tooth that a shark has depends on its diet and feeding habits. In some formations, shark's teeth are a common fossil.