Tui De Roy / Flightless cormorant (Phalacrocorax harrisi) with Slate pencil urchin (Eucidaris sp) in beak. Punta Albemarle, Isabela Island, Galapagos.

Tui De Roy / Flightless cormorant (Phalacrocorax harrisi) swimming with Slate pencil urchin (Eucidaris sp) in beak. Punta Albemarle, Isabela Island, Galapagos.

Tui De Roy / Flightless cormorant (Phalacrocorax harrisi), two on rocks. Bird with Slate pencil urchin (Eucidaris sp) in beak with more Sea urchins below. Other bird sitting on nest. Punta Albemarle, Isabela Islan...

Tui De Roy / Flightless cormorant (Phalacrocorax harrisi) swimming with Slate pencil urchin (Eucidaris sp) in beak. Punta Albemarle, Isabela Island, Galapagos.

Tui De Roy / Flightless cormorant (Phalacrocorax harrisi) pair with Starfish (Asteroidea) and Slate pencil urchin (Eucidaris sp) scattered at feet. Punta Albemarle, Isabela Island, Galapagos.

Tui De Roy / Flightless cormorant (Phalacrocorax harrisi) in mid-air. Coming ashore with Slate pencil urchin (Eucidaris sp) in beak. Punta Albemarle, Isabela Island, Galapagos.

Tui De Roy / Flightless cormorant (Phalacrocorax harrisi) pair billing with Slate pencil urchins (Eucidaris sp) on rocks below. Punta Albemarle, Isabela Island, Galapagos.

Tui De Roy / Flightless cormorant (Phalacrocorax harrisi) pair billing with Slate pencil urchins (Eucidaris sp) on rocks below. Punta Albemarle, Isabela Island, Galapagos.

Tui De Roy / Flightless cormorant (Phalacrocorax harrisi) with Slate pencil urchins (Eucidaris sp). Punta Albemarle, Isabela Island, Galapagos.

David Fleetham / Close look between the spines of Slate pencil sea urchin (Heterocentrotus mammillatus), Hawaii.

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus) in reef scene, Hawaii.

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus), pennantfish / bannerfish (Heniochus diphreutes) and moorish idols (Zanclus cornutus) on reef, Hawaii.

David Fleetham / Red liomera crab (Liomera rubra) female holding a tail full of eggs in a slate pencil sea urchin (Heterocentrotus mammillatus) at night, Hawaii.

Pascal Kobeh / Slate pencil urchin (Heterocentrotus mamillatus), New Caledonia, Pacific Ocean.

Fred Bavendam / Slate Pencil Urchin (Heterocentrotus mammillatus) pair attached to rock wall, Kona, Hawaii

David Hall / Slate pencil sea urchin {Heterocentrotus mammillatus} Red Sea - nocturnal

Norbert Wu / Slate Pencil Urchin (Heterocentrotus mammillatus) spines are stony and used for wind chimes, Hawaii

Norbert Wu / Pencil Urchin (Ctenocidaris perrieri) and Brittle Star (Ophionotus victoriae) similar to deep sea species, New Harbor, Antarctica

Jeff Rotman / Spines of Slate pencil sea urchin {Heterocentrotus mammilatus} Red Sea.

Jeff Rotman / Slate pencil sea urchin {Heterocentrotus mammillatus} Hawaii, Pacific Ocean

David Fleetham / Giant / Commerson's frogfish (Antennarius commerson), juvenile, on Red slate pencil sea urchin (Heterocentrotus mammillatus), Hawaii.

David Fleetham / Hawaiian turkeyfish (Pterois sphex), endemic, and slate pencil sea urchin (Heterocentrotus mammillatus), Hawaii.

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus), Pennantfish (Heniochus diphreutes) and Pyramid butterflyfish (Hemitaurichthys polylepis), Hawaii.

David Fleetham / Commerson's / Giant frogfish (Antennarius commerson), on Red slate pencil sea urchin (Heterocentrotus mammillatus), Hawaii.

David Fleetham / Commerson's / Giant frogfish (Antennarius commerson), juvenile, perched on a Red slate pencil sea urchin (Heterocentrotus mammillatus), Hawaii.

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus) and Pyramid butterflyfish (Hemitaurichthys polylepis), Hawaii.

David Fleetham / Slate pencil sea urchin (Heterocentrotus mammillatus), being held by couple snorkeling, Hawaii.

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus) and Pyramid butterflyfish (Hemitaurichthys polylepis), Hawaii.

David Fleetham / Close-up of Horned helmet shell (Cassis cornuta) hunting Red Pencil Urchin (Heterocentrotus mamillatus), Hawaii, USA, Pacific Ocean.

David Fleetham / Day octopus (Octopus cyanea) releasing an ink cloud to escape predator on reef, as Red pencil urchin (Heterocentrotus mamillatus) rests behind, Hawaii, USA, Pacific Ocean.

David Fleetham / Psychedelic wrasse (Anampses chrysocephalus) juvenile swimming in reef, with Slate pencil sea urchin (Heterocentrotus mammillatus) behind, Hawaii, Pacific Ocean.

David Fleetham / Commerson's frogfish (Antennarius commersoni) juvenile sheltering among spines of Slate pencil sea urchin (Heterocentrotus mammillatus), Hawaii, Pacific Ocean.

David Fleetham / Close up of skin between the spines of a Slate pencil sea urchin (Heterocentrotus mammillatus), Hawaii, Pacific Ocean.

David Fleetham / Three scuba divers swimming over coral reef looking at Slate pencil sea urchins (Heterocentrotus mammillatus), Molokini Marine Preserve, Maui, Hawaii, Pacific Ocean. Model released.

Georgette Douwma / Composite image of echinoderms on black background. Species present: - Top row from left: Yellow sea cucumber (Colochirus robustus) and Lampert's sea cucumber (Synaptula lamperti), Black sea c...

David Fleetham / Red slate pencil urchin shrimp (Levicaris mammillata) sitting on the spine of a Red slate pencil urchin (Heterocentrotus mamillatus), Hawaii, Pacific Ocean.

David Fleetham / Slate pencil sea urchin (Heterocentrotus mammillatus), close up view between its spines, Hawaii, Pacific Ocean.

David Fleetham / Yellowmargin moray eel (Gymnothorax flavimarginatus) sheltering in a crevice behind a Slate pencil sea urchin (Heterocentrotus mammillatus), Hawaii, Pacific Ocean.

David Fleetham / Slate pencil sea urchin (Heterocentrotus mammillatus) using its spines to attach to a rock crevice, Hawaii, Pacific Ocean.

David Fleetham / Close up look between the spines of a Slate pencil sea urchin (Heterocentrotus mammillatus), Hawaii, Pacific Ocean.

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus) on a reef, with two swimmers free diving in background, Molokini Marine Preserve, Maui, Hawaii, Pacific Ocean.

David Fleetham / Ten-lined urchin (Eucidaris metularia) nestled on a reef, close up, Hawaii, Pacific Ocean.

David Fleetham / Slate pencil sea urchin (Heterocentrotus mammillatus) on a reef with Black triggerfish (Melichthys niger) and a Bluestripe snapper (Lutjanus kasmira) swimming above, Maui, Hawaii, Pacific Ocean.

David Fleetham / Coral reef with Slate pencil sea urchins (Heterocentrotus mammillatus), Pennantfish (Heniochus diphreutes) and Pyramid butterflyfish (Hemitaurichthys polylepis) and a diver holding a light, Hawaii. Mo...

David Fleetham / Slate pencil sea urchin (Heterocentrotus mammillatus) close up of shell and spines, Pacific Ocean, Hawaii, USA.

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus) on coral reef with two female free divers in the background, Molokini Marine Preserve, Maui, Hawaii. Model released.

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus) and Bluefin trevally (Caranx melampygus), Hawaii.

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus) on coral reef with Pyramid butterflyfish (Hemitaurichthys polylepis), Hawaii.

Francisco Marquez / Pencil tip hedgehog sea urchin (Eucidaris thouarsii) on white background, Islas Marias Archipelago, Mexico.

David Fleetham / Underside of a slate pencil sea urchin (Heterocentrotus mammillatus), Hawaii.

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus) Pennantfish (Heniochus diphreutes) and Pyramid butterflyfish, (Hemitaurichthys polylepis) swim through the background. Hawaii.

David Fleetham / Slate pencil sea urchins (Heterocentrotus mammillatus) in Hawaiian reef scene with Black triggerfish (Melichthys niger) Hawaii.