Animal Care, Blog, Did You Know

Sea Urchins’ Teeth and Aristotle’s Lantern

Did you know? The Purple Sea Urchin has protective large spines, pincers (called pedicellariae), tube feet and five teeth, arranged in a circle at the bottom of its body, that it uses to scrape algae from rock surfaces?

Here’s what Aristotle had to say about this arrangement of teeth: “In reality the mouth-apparatus of the urchin is continuous from one end to the other, but to outward appearance it is not so, but looks like a horn lantern with the panes of horn left out.” Oh, yeah, in addition to philosophy, Aristotle wrote about Urchins in The History of Animals. In later years this lantern-like mouth came to be known as “Aristotle’s Lantern”. Possibly because of the drawing he included, which you can see here.

The urchin uses its Horn Lantern (if you’re Aristotle) or Aristotle’s Lantern (if you’re every other biologist in the world) to scrape away algae growing on rocks and create a depression that becomes the sea urchin’s hideaway. Sometimes a sea urchin grows larger than its dugout depression and gets stuck — for life. Once trapped, the urchin can only feed on particles that drift by with the current.

Whichever lantern you use to refer to an Urchin’s mouth, those teeth are pretty formidable. In areas without a lot of predators (like sea stars and sea otters), purple urchins are known for dramatically altering the kelp forest ecosystem and leaving behind a vast bare area, known as an urchin barren.

Blog, Did You Know

Did you Know? Moray Eels

Moray Eel in the Discovery Center Gallery at the Living Coast.

Here are five things you need to know about Moray Eels — and one extra Living Coast tidbit.

The moray eel gets its color from the protective mucus it secretes that covers its body. This mucus contains a substance that is toxic to some species.
This fish has poor eyesight but a very good sense of smell.
Morays hatch in Baja California’s warmer water and the larvae drift north to southern California.
They can live up to 30 years
Although the species name, mordax, means “prone to bite,” these animals are actually very timid and do not intentionally bite humans. Lacking gill covers, they must pump water across their gills by opening and closing their mouths, resulting in their sharp teeth being exposed. This makes them appear aggressive, but they are just breathing

Snarky the Eel — Not aggressive. Just breathing. Snarky, though.

Little-Known (OK, Widely Known) Living Coast Fact:Our Eel has a column in our newsletter in which he describes the Featured Animal and then says something snarky about it. Want to check him out? We send just 2 newsletters a month! Click here for a quick sign-up.

Animal Care, Blog, Media

In the News: KPBS looks at Fins & Feathers

Dwane Brown came to the Living Coast recently where we discussed which traits humans share with fish, and how wetlands and habitat losses affect local bird communities. Check out the story about Our Wild San Diego below!