Nurse sharks are gentle and don't attack people actively. Nurse sharks are viviparous, the gestation period is 10 ~ 12 months, and they lay 20 ~ 40 eggs at a time. But because the larvae will kill their own kind in the mother fish's stomach, it is called fierce competition. Young fish can be up to 40 cm long at birth. Nurse sharks are mainly nocturnal animals. They usually lie on the sandy seabed or hide in caves to rest during the day and come out to hunt at night.