Sharks are a group of cartilaginous fish known for their streamlined bodies and sharp teeth. They belong to the class Chondrichthyes, which also includes rays and skates. Sharks are found in oceans worldwide and play a crucial role in marine ecosystems as apex predators, helping to maintain the balance of marine life. There are over 500 species of sharks, varying in size from the small dwarf lanternshark, which is about 8 inches long, to the massive whale shark, which can reach lengths of up to 40 feet. Sharks have keen senses, particularly their ability to detect electrical fields and vibrations in the water, aiding them in hunting.