Sharks have cartilaginous skeletons and sandpaper-like skins. They also have fleshy fins and five to seven gill slits on either side of the head. Adult males have paired claspers used during mating. Most sharks are solitary, but some congregate during their mating season. The majority are harmless and interact peacefully, but some are potentially dangerous to humans when conditions cause sharks to misidentify their prey.
The number of scuba divers attacked by sharks while wearing scuba equipment is extremely low. Some species present a greater risk than others, and it is important you learn about species in the area you intend to dive and if necessary, avoid known habitats and swimming during peak feeding times, usually twilight.