There are about 40,000 pairs and 80,000 Chinese horseshoe crabs, which have survived on Earth for 450 million years, and are known as "living fossils".

In March 2019, the World Conservation Union (IUCN) formally updated the Chinese horseshoe crabs to endangered on the IUCN Red List.

Chinese horseshoe crabs, along with American horseshoe crabs, round-tailed horseshoe crabs, and southern horseshoe crabs, are the only four species of horseshoe crabs left in the world, of which Chinese horseshoe crabs are mainly distributed in the waters of the Beibu Gulf, and people in Beihai can often see small horseshoe crabs of the Chinese horseshoe crab and round-tailed horseshoe crabs in the mudflats. Horseshoe crab blood is rich in copper ions hemocyanin, which makes the horseshoe crab become one of the few "blue-blooded animals" on earth.