50 interesting facts about sea urchins
Amazing creatures, sea urchins, have long tormented the minds of zoologists. These underwater animals are very interesting from a biological point of view, and the conditions in which some of their species live seem to be truly extreme. But people are willing to collect them, especially in shallow water, as sea urchins in some countries are enviable food. However, most tourists who have tried them do not share this opinion.
Facts about sea urchins
1. Animal sea urchins are echinoderm mollusks.
2. These amazing creatures have long been under the close attention of zoologists, as sea urchins are very interesting from a biological point of view.
3. These underwater animals attract with their unusual appearance and physiology.
4. In total, there are about 940 species of sea urchins in nature, and in our time, zoologists continue to discover more and more of their species.
5. Sea urchins are one of the longest living animals on Earth. They are older than dinosaurs. Their first species appeared on our planet about 450 million years ago.
6. These animals are able to easily withstand the monstrous pressure of the water column. Research probes have detected them at depths of up to 7 kilometers.
7. These animals live only in very salty waters, therefore, where large rivers partially desalinate the seas and oceans into which they flow, sea urchins are not found.
8. The size of the largest sea urchins reaches 30 centimeters in diameter, while in the smallest it does not exceed 2 centimeters.
9. The conditions in which some of the species of sea urchins live seem truly extreme.
10. They are also found not only in warm waters. Some sea urchins even live in the Antarctic climate.
11. Sea urchins can drill holes for themselves even in strong granite rocks.
12. The record holder for the length of the spines among all sea urchins are diadem hedgehogs (the length of their spines is up to 70 cm with a shell diameter 10 times smaller), and in flat hedgehogs their length does not exceed 2 millimeters.
13. Also diadem sea urchins glow in the dark.
14. Most sea urchins lay eggs, but some give birth to live offspring, like mammals.
15. Sea urchins got their name for a reason. Their entire body is covered with movable sharp needles, although there are a small number of species lacking this feature. Basically, the needles serve to protect against predators. Their long needles are a formidable and effective weapon. But needles serve them not only for protection, but also for movement, as well as for obtaining food.
16. On the body of sea urchins there are over 1000 tiny legs with suction cups on them. Thin legs pass through the shell. On their feet are suction cups, with the help of which these animals move.
17. In addition, their legs are adapted for burrowing. The legs of sea urchins are also located on the back, they serve to sense the environment. And some species have adapted their unusual limbs to obtain food and cleanse their shells of pollution.
18. Sea urchins do not have bones. Their body is covered with strong calcium plates that cover the body like an orange peel. These plates are symmetrical to each other, they are strong enough and protect the internal organs from mechanical damage.
19. By the annual rings on the shell of these animals, one can determine their age in the same way as by the growth rings of trees.
20. Sea urchins have five jaws at once, each of which has one tooth. These teeth can move independently of each other. Their teeth grow throughout their lives. Thanks to friction against each other, they grind off and always remain sharp enough. The mouth of these animals is somewhat reminiscent of a beak.
21. The eyes of sea urchins are located in the upper part of the body, and the mouth is in the lower.
22. Puberty in sea urchins occurs only 2-3 years after birth.
23. And in some of their species - even after 5 years. That's why they reproduce so slowly.
24. Sea urchins reproduce by external fertilization - they release sperm and eggs directly into the water.
25. First, the animal passes through the larval stage. Until its final transformation, it moves along the bottom along with other plankton.
26. In food, sea urchins are completely illegible. They feed mainly on algae, but are also not averse to eating small invertebrates, the remains of dead fish and other small living creatures.
27. A large brood needs a lot of food. Hedgehogs literally eat all the coral reefs. Some of them even eat each other.
28. They continue to grow throughout life.
29. Most species of sea urchins are nocturnal.
30. One of the species of sea urchins cannot roll back if they are knocked over. In this case, these animals die.
31. Amazing sea urchins are always a close object of attention for lovers of snorkeling or scuba diving.
32. These strange creatures look very unusual, and many people want to touch them, but this should absolutely not be done.
33. You can easily prick yourself on the spines of a sea urchin, and such injections are very painful.
34. If you step on a sea urchin, its needles, like fragile glass, break into many fragments, sticking into the body. Their extraction is a very complicated and painful operation, which only experienced doctors can do.
35. And some types of sea urchins are poisonous, and therefore very dangerous.
36. Poison is contained in the mucus on their spines.
37. During low tide, sea urchins do not risk staying on the shore, where they can become easy prey. Usually they either hide in burrows or burrow into the sand.
38. Close relatives of sea urchins, according to scientists, are sea cucumbers.
39. Some small fish have learned to have a mutually beneficial coexistence with sea urchins.
40. They hide between its needles in case of danger, and in response they eat the parasites that have stuck around it, from which the hedgehog cannot get rid of on its own.
41. On average, sea urchins live for about 30 years. But some types of sea urchins are real centenarians. In the wild, they live up to 200 years.
42. Despite their own pricklyness, they often become victims of predators. A large number of different animals prey on these echinoderms. They are readily eaten by fur seals, birds, fish, lobsters and starfish.
43. One of the most formidable enemies of sea urchins is the sea otter. He breaks the needles of his prey with a stone, and then eats her insides. Sea otters eat so many sea urchins every day that their entire insides turn purple due to the pigment contained in these echinoderms.
44. Humans also pose a considerable danger to the diversity of species of this class. Sea urchins in many countries are part of the national cuisine. Their caviar is mainly used for food.
45. Many people are willing to collect sea urchins, especially in shallow water, as sea urchins are a delicacy in some countries. But most tourists who have tried them do not share this opinion.
46. There is a whole fishery for their breeding and catching. Due to human activities and active fishing, many species are endangered.
47. Although sea urchins are distributed throughout the world. They are found in all oceans and in almost all seas, including the coldest ones.
48. There are only three seas in which not a single species of sea urchins lives - the Caspian, the Black, and, of course, the Dead Sea.
49. These animals are very useful creatures. They absorb carbon dioxide like plants. And sea urchins reduce the level of radiation in the oceans.
50.Sea urchins are an essential part of the ocean ecosystem.