The whitetip reef shark (Triaenodon obesus) is a species of shark in the family Carcharhinidae, and the only member of its genus. A small shark usually not exceeding 1.6 m in length, this species is easily recognizable by its slender body and short but broad head, as well as tubular skin flaps beside the nostrils, oval eyes with vertical pupils, and white-tipped dorsal and caudal fins. One of the most common sharks found on coral reefs. It is typically found on or near the bottom in clear water, at a depth of 8–40 m.
During the day whitetip reef sharks spend much of their time resting inside caves. At night whitetip reef sharks emerge to hunt bony fishes, crustaceans, and octopus in groups, their elongate bodies allowing them to force their way into crevices and holes to extract hidden prey. Individuals may stay within a particular area of the reef for months or years, frequently returning to the same shelter. This species is viviparous, in which the developing embryos are sustained by a placental connection to their mother. One of the few sharks in which mating has been observed in the wild, receptive female whitetip reef sharks are followed by prospective males, which attempt to grasp her pectoral fin and maneuver the two of them into positions suitable for copulation. Females give birth to one to six pups every other year, after a gestion period of 10–13 months.
Only rarely do the white fin sharks of the reef become aggressive towards the man, even if, intrigued, they can push themselves to examine the swimmers closely. However, spearfishing enthusiasts run the risk of being bitten by individuals trying to steal their captured prey.
This species is caught for food purposes, although there have been documented cases of poisoning as a result of the consumption of their meat. The International Union for Nature conservation lists the white fin shark of the reef as a species close to the threat of extinction, in fact the number of specimens decreased as a result of the increase in unregulated fishing activities.
(extract from Wikipedia)