Pleurobranchaea californica is a side-gilled nudibranch (order Notaspidea), found on the Pacific coast of North America from Port Orford, Oregon to San Diego, California.A deep water sea slug, it is found at depths between 30-1200 feet (9-365 meters).This sea slug has the honor of being one of the largest opisthobranchs in the world.It lives on sandy and muddy substrates and has a surprisingly wide and generalist diet, foraging upon large variety of invertebrates, small fish, and even other individuals of its own species (Miller 1999).Studies indicate this slug can learn to avoid prey with stinging defenses and to avoid specific prey species based on aposematic odors (Noboa and Gillette 2013). A video of this avoidance behavior can be seen here: https://www.youtube.com/watch?v=-EuVvkQ3VYM.
