Invertebrates
Clown Nudibranch
Triopha catalinae · also called clown dorid, mosaic sea slug
Bright orange projections scattered across a pale, translucent body give a clown nudibranch an almost painted appearance as it grazes slowly across bryozoan-covered rocks in the cold coastal waters of the northeastern Pacific.
Overview
The clown nudibranch, Triopha catalinae, is a sea slug native to rocky coastal habitat along the Pacific coast of North America. Its vivid orange patterning against a pale body, bryozoan-based diet, and preference for cooler waters over tropical reefs make it one of the more visually striking cold-water nudibranchs found anywhere.
Colour as a warning
Like many brightly coloured nudibranchs, the clown nudibranch’s vivid orange markings are thought to function as a warning signal to potential predators, advertising an unpalatable taste rather than serving any camouflage purpose.
Status
Not Evaluated for conservation status, found across suitable rocky coastal habitat along the Pacific coast of North America.
Clown Nudibranch: common questions
Why is it called the clown nudibranch?
Its bright orange tubercles and gill projections scattered across a pale, translucent body give it a colourful, patterned appearance reminiscent of face paint, inspiring both the "clown" nickname and its alternative name, the mosaic sea slug.
What does the clown nudibranch eat?
It is a carnivore that feeds mainly on bryozoans, small colonial invertebrates that encrust rocks and seaweed in its coastal habitat.
Why is the clown nudibranch so brightly coloured?
Its vivid orange colouring is thought to serve as a warning to potential predators that it is unpalatable, a defensive strategy shared by many brightly coloured nudibranch species.
Where is the clown nudibranch found?
It is native to rocky coastal habitat along the Pacific coast of North America, favouring the region's cooler waters.