Natural Sciences

That Healthy Glow

Making the garden-variety slug green with envy

Please forgive your garden-variety slug if it turns green with envy.

What self-respecting mollusk wouldn’t covet the rainbow-like beauty of Hermissenda opalescens? These colorful critters are only two inches long, but what they lack in size they more than account for in otherworldly iridescence.

The opalescent sea slug doesn’t actually generate that warm glow from within—proteins in their blood capture and reflect available light. Scientists believe this evolutionary adaptation might advertise to predators the sea slug’s unsavoriness.

Though they live less than a year, these dwellers of tidal pools can be spotted from spring through late summer along the coast from Alaska to Northern California—and at the new Charleston Marine Life Center, featuring exhibits on deep-water habitats, marine mammals and research by the Oregon Institute of Marine Biology, which runs the center.


Photo credit: Reyn Yoshioka