Wechat avatar means shark.

WeChat avatar uses the meaning of shark: extremely sharp, always forward, long life and happiness.

Sharks belong to cartilaginous fish, a subclass of vertebrates and a marine animal. A few species enter fresh water, which is a group of medium and large marine fish with fast swimming speed.

The endoskeleton of sharks is completely composed of cartilage, which is often calcified, but there is no real bone tissue. The exoskeleton is not developed or degenerated. The body is often covered with skin teeth (thin-walled tissue scales), with various teeth and hard muscles, but the membranous bone never existed and the skull is seamless. The upper forehead is composed of palatal cartilage and the lower forehead is composed of Mayer cartilage.

Protect the status quo

Shark is an ancient fish. Judging from many fragments of shark teeth and spine unearthed, its fossils appeared 3.5-4.65438 billion 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 and late sexual maturity, and the reproductive rate is every two years 1 time, and the reproductive rate is extremely low.

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 to eat shark fin and Asian ground meat as food and medicine. It is a symbol of wealth and status, and its price is extremely expensive.

1999, whale sharks, basking sharks (also called elephant dumplings) and man-eating sharks have been listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), and trade activities are strictly prohibited. China South China Sea is rich in shark resources and diverse in species. In 200 1 year, the relevant departments of Guangdong Province listed whale sharks and basking sharks as key protected species of aquatic wildlife.