Sea urchins are colorful and resistant: Lifeform of the week

Sea urchins are spiny sea creatures that are a part of one of the best-preserved groups of animals in the fossil record. They’ve been around for some 200 million years, so they must be doing something right. Their preservation in the fossil record is thanks to their mega-hard shells. And sea urchins are still considered animals despite their lack of brains or blood.

What are sea urchins?

Sea urchins are echinoderms, that is, marine invertebrate animals. The famous starfish (or sea...