Blue Ocean Slug

Photograph by Daniel Coleman, My Shot

The blue ocean slug, a type of nudibranch, is a striking specimen with extraordinary hues that provide two types of camouflage. On the sea surface, the animal’s blue topside provides protection from hungry birds above, while its silver subsurface hides it from predatory fish looking up from below. The blue ocean slug is itself a formidable predator that feasts on dangerous animals like the Portuguese man-of-war. Not only is the slug unfazed by the man-of-war’s stinging cells, it ingests them and transports the toxic weapons internally to the ends of its own appendages for self-defense.