What kind of animal is a sand dollar?

Sand dollars, also known as "sand money", "sea money", belongs to the sea urchins under an order, the shape of the cake, so it is also known as "cake sea urchin", and because it looks like a silver coin, hence the name "sand dollars". They are also called "cake sea urchins" because they look like silver coins, hence the name "sand dollars". But in fact, only after the death of the sand dollar is like this, dry and white and round.

Sand dollars in the living, its color is more difficult to describe, usually dark purple grayish brown, so you can judge from the color of their bodies to determine the state of their lives, if they have become the above picture of the silver-white, then they are already dead.

Sand dollars generally live in the intertidal or subtidal beach surface, sometimes they will also be buried in the sand, they can also live in the water depth of about 3,000 meters in the sea.

It was mentioned that the sand dollar is a member of the sea urchin family, so the sand dollar and the sea urchin are close cousins in the same order, and their shells are both covered with dense thorns. However, the thorns of the sand dollar are shorter and not as hard and sharp as those of the sea urchin, so you may get stabbed if you touch them.

The thorns of the sand dollar are very small and soft, and feel plush and fuzzy like a stuffed doll. These soft and tiny little fluffy hairs help the Sand Dollar dig into the sand, thus allowing itself to dive into the sand. Not only that. These little fluffy hairs also act like countless tentacles to help the sand dollar get its food into its mouth, which is located in the middle part of its belly.

The anus of the sand dollar is also located in the middle of the abdomen, not far from the mouth, so they can eat and defecate at the same time.

The body of the sand dollar is smooth on one side, and slightly raised on the other with petal-like patterns, which are very pretty. The name of these patterns is called the five-panel step band, and it works by allowing seawater to enter the sand dollar's body, thus assisting the movement of the sand dollar with waves. But they really rarely move, food is with the sea water to their side, unless there is a really rich food, they may be reluctant to move a few times, at least when they will only move about 10 centimeters a day, the longest will not exceed 1 meter, is really a very "Buddhist" creatures.

The sand dollars are group-living creatures because they move slowly and are used to discharging sperm and eggs on the seabed, so if they want to reproduce and grow their own family, they can only do so in a group, so it's rare to see a single sand dollar, and basically they are a group of a group of people living in a piece of land.

In fact, basically no marine life will eat sand dollars, first of all, because their shell is very hard, and secondly, because the edible part of their body is very little, less meat and more bones, naturally few marine life will be interested in them.

Some of the sand dollars live in the intertidal zone, and after the tide goes out, they will be washed up on the beach; there are also some of them live in the sand of the subtidal zone, and after the tide goes out, they will also appear on the beach. But if they don't make it back to where there's salt water in time, they dehydrate and die in just a few minutes, so the cause of death for those sand dollars on U.S. beaches is really quite simple.

At this time, many of our friends may ask if we have this kind of marine life in China, then of course we do, since it is a marine life, they can be seen on the sandy beaches of shallow seas, intertidal zones as well as subtidal zones all over the world.

But the sand dollar, like other sea urchin creatures, is a real "social fear", as long as there are strange creatures close to them, they will immediately run away, although the action is slow, but they will also immediately burrow into the sand to avoid it.