Is sea urchin poisonous?

If you have seen the appearance of a sea urchin, you must be quite surprised, because the whole body of the sea urchin is covered with hard spines, and these spines will definitely make friends who see it for the first time feel creepy. The spines of sea urchins are relatively long, and there may be toxins at the tips, so when friends see native sea urchins, it is best not to touch them with their hands to avoid puncture wounds.

Are sea urchin spines poisonous?

Perhaps those of you who have traveled to the beach or live by the sea have experienced being pricked by the spines of a sea urchin. When pricked by a sea urchin's spine, not only will the wound become red and swollen, but the spine will remain in the wound, causing it to become inflamed and discolored, and the entire body will become numb and painful. If you don’t have this experience, you must deal with it immediately if you get pricked. Why is this so? This brings us back to the topic mentioned at the beginning of our article: Are sea urchin spines poisonous? Let’s take a look at whether sea urchin spines are poisonous.

The shell of a sea urchin is covered with spines, is generally about 1-2 cm long, 1 or 2 mm thick, and is conical in shape. The crown sea urchins found in the Caribbean Sea have spines that are 10-20 cm long. The thorns themselves are hollow and fragile, and broken thorns can regrow. The spines are connected to the base with a ball-and-socket joint and can point in any direction. If there is even a slight contact, the spines will converge towards the point of contact. This protects the urchins from predators, and some urchins have more toxic sacs at the end of their spines. The spines of the sea urchin are generally short and blunt, which can resist the impact of waves and help retain moisture on the surface of the sea urchin.

In addition to spines, sea urchins also have forked spines to defend against foreign enemies. The forked spines are scattered all over the body surface of the sea urchin and the periorbital area. The forked spine area of ​​some sea urchins is separated from the thorn area. For example, the forked spines of the white-spined three-row sea urchin are concentrated in the striae area and are purple-red in color, which can scare away enemies. The forked spines are supported by calcareous rod-shaped bone plates, with jaws and several poison sacs at the top. The jaws can bite, and the poison sacs can anesthetize or poison small animals.

Sea urchins like to live in reef forests or crevices in rocks below the intertidal zone rich in seaweed, as well as in shallow sea areas with harder muddy and sandy materials, hiding in crevices among rocks, between reefs, in mud or coral reefs. It lives in the shade and hides during the day and comes out at night, relying on thorns to defend against enemies. The spines of sea urchins are long or short, pointed or blunt, and the structure of the spines varies from species to species. A kind of pencil sea urchin is abundant in the coral reefs of Hainan Island. It looks like a blooming flower and is commonly known as the cigarette holder sea urchin. Because its spines are very thick and masculine, it can be used as a cigarette holder. Some species have very long spines, up to more than 20 centimeters.