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. It ranges from nine months to as long as 22 months in spiny dogfish. Depending on the species, sharks can produce between 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. Although they are slow and sluggish, basking sharks and whale sharks are considered dangerous because of their large size. The most important sense the shark uses to detect its prey is sound.