That means their eggs are fertilized in the female's body. Sperm travels along a groove on the clasper into the female's body. Some sharks lay egg-filled cases on the bottom of the ocean, called devil's wheelbarrows or mermaid's purses. The gestation period in sharks varies with each species. Depending on the species, sharks can produce 2 to 135 young at one time.
All sharks are predators.
Many shark attacks are caused by people getting too close to sharks, or provoking and threatening them. Seventeen other species of sharks have also attacked humans. They are considered less dangerous, but are aggressive if threatened or disturbed. They include lemon sharks, blacktip reef sharks, nurse sharks, wobbegongs, sandtiger sharks and spitting sharks. Although they are slow and sluggish, basking sharks and whale sharks are considered dangerous because of their large size.