Gallery: Sea Urchins

Purple urchins

Urchin spines

An adult purple sea urchin. — (Image credit: Claire Fackler, NOAA National Marine Sanctuaries)

The urchin's spines help it skewer food and protect itself against predators.

Spawning female urchin

The urchins breed annually around January, February and March.

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Urchin larva

The urchins start out as free-floating larvae that may swim and feed for several months.

Urchin metamorphs

Urchins undergo metamorphosis from a larval form to an adult form.

Inside-out urchin

Sea urchin larvae turn inside-out as the larvae metamorphose to adults.

Sea urchin genome

(Image credit: Mount Desert Island Biological Laboratory)

Scientists recently sequenced the genome of the purple sea urchin.

Tanya was a staff writer for Live Science from 2013 to 2015, covering a wide array of topics, ranging from neuroscience to robotics to strange/cute animals. She received a graduate certificate in science communication from the University of California, Santa Cruz, and a bachelor of science in biomedical engineering from Brown University. She has previously written for Science News, Wired, The Santa Cruz Sentinel, the radio show Big Picture Science and other places. Tanya has lived on a tropical island, witnessed volcanic eruptions and flown in zero gravity (without losing her lunch!). To find out what her latest project is, you can visit her website.