Collector Urchin.
A purple-spined urchin with a habit of decorating itself with shells, algae and debris — and a powerful tool against invasive seaweed.
The collector urchin gets its name from its habit of picking up bits of shell, algae and rubble and carrying them on top of its body, a behavior that may help with camouflage, sun protection or simply weight to keep from being washed away.
Collector urchins are voracious grazers of algae, including invasive species. The State of Hawaiʻi runs an urchin hatchery on Sand Island that has released millions of hatchery-raised collector urchins onto Oʻahu reefs as a biological control against smothering invasive macroalgae like leather mudweed.
Their roe (called uni) is harvested in many parts of the world but is rarely eaten in Hawaiʻi. Take of any urchin from State waters requires special permits.
More species in this group.
Day Octopus
A daytime hunter and master shapeshifter, Hawaiʻi's most commonly seen octopus can change color and texture in under a second.
Chambered Nautilus
A living fossil whose ancestors swam alongside dinosaurs, the nautilus drifts through deep reefs in a perfect spiral shell.
Hawaiian Bobtail Squid
A thumb-sized squid that hides in plain sight using bioluminescent bacteria to erase its own shadow under the moon.
Textile Cone Snail
A beautiful but dangerous predator that fires a venomous harpoon to paralyze fish — and whose toxins inspire modern medicine.