Sharks are oviparous animals. When oviparous sharks lay eggs, their egg sheaths are thick, so that they can attach to rocks or seaweed to resist predators. Shark's eggs are large and there is no shortage of nutrients.

The number of times a female shark ovulates is limited. Eggs are bag-shaped or spiral, and are fixed in coral reefs, marine benthos or cracks after spawning. After these eggs hatch in a few days or weeks, the sharks will leave the young sharks and let them live independently.

Extended data:

Shark is an ancient fish. Judging from many fragments of shark teeth and spine unearthed, its fossils appeared 3.5-4. 1 100 million years earlier than dinosaurs. In this long history, some species of sharks have disappeared through natural selection, but there are still some vulnerabilities in more than 300 species of sharks, such as slow growth, late sexual maturity, and extremely low reproduction rate every two years/kloc-0 times.

The indiscriminate hunting and killing of sharks by human beings is the main reason for the decrease of shark population. Human hunting is mainly used for eating shark fin and Asian minced meat for food and medicine. It is a symbol of wealth and status, and it is extremely expensive.

People's Network-Shark eggs look like this! Looks like a torpedo