? "Sand coin", also called "sand money" or "sea money", is a kind of marine animal. Its shape is mostly disc-shaped and looks like a metal coin, hence the name. In different countries, people give it more vivid names, such as sea biscuits, sand cakes and so on.

Stranded sand coins

Living habits: The legend of sand coins first appeared in Atlantis. Now it often appears on American beaches, so the English word is "Sand Dollar". It is a typical marine social animal. Sand coins are inseparable from the ocean. Once they leave the sea, they will die immediately. Shabi lives in a deep and wide range in the ocean. Shallow in intertidal zone or subtidal zone, with a depth of 50-150m, or buried in sand, with the deepest depth reaching the seabed and a water depth of 3000m. It is a place for their daily activities.

Groove structure diagram

Physical characteristics: Sha Qian is surrounded by tiny and fluffy spines and is the "cousin" of sea urchins. These tiny fluff spines are like the mechanical arms of excavators, which are mainly used to dig sand, making it easier for your body to dive into the sand. The surface of the thorn is covered with cilia, and with its viscosity, food can be easily sent to the mouthparts in the center of the abdomen. Its anus is behind its tail. On the other hand, live sand coins are purple-brown, and they have many tentacles. With these tentacles, they can rotate, move and bury themselves in the sand.

Moving patterns of live sand and coins

Food source: Because the movement of sand coin needs the help of the wave thrust, its pins will also be used to collect food. The plankton in the deep water area and the organic matter hidden in the sand bottom are the main food sources of sand coins.

God? Enemy: In nature, the five elements interact, and any animal has its own natural enemies, including sand coins. Because "Shabi Fish" has little meat and hard shell, it can be used as inexhaustible fish and shellfish in the food chain in the rich ocean. Few people like to eat this strange creature as thin as a coin. But one of the marine cod occasionally patronizes the Shabi group. After reading it, many foodies can finally give up their desire to covet fresh species.

Contribution to mankind: Sand coins are hidden in the sea sand, often exposed on the beach at low tide, and often become children's playthings or biological specimens, which are displayed in the Ocean Museum. After the storm, the overwhelming waves will wash the dead sand coins ashore, which is why pieces of sand coins are often found on the beach.

The sand coins that died on the beach were white.

The area of the ocean is about three times that of the land, and there are countless marine life, including many strange species unknown to human beings. Whenever a new creature appears, people will better understand the characteristics of marine life and the endless mystery of the ocean through it, and feel the surprise and shock brought by every mysterious ocean.