Marine Wildlife Encyclopedia
Spanish Dancer Hexabranchus sanguineus
The largest of the nudibranchs is the Spanish dancer—so called because when it swims, the undulating movements of its flattened body are reminiscent of a flamenco dancer. Adults are brightly but variably colored, generally in shades of red, pink, or orange, sometimes mixed with white or yellow.
While resting, crawling, or feeding, the lateral edges of the Spanish dancer's mantle are folded up over its back, displaying the less colorful underside. If disturbed, it will escape by swimming away, exposing its bright colors and possibly startling potential predators. Spanish dancers are specialist predators that feed only on sponges, particularly encrusting species, from which they modify and concentrate certain distasteful compounds in their skin to use as another defense against predation. They have external gills for respiration, which are extensively branched and attached to the body wall in distinct pockets and which cannot be retracted. Like all nudibranchs, the Spanish dancer is hermaphroditic, but it requires a partner in order to reproduce.
Spanish Dancer Reproduction
To protect its egg cluster, called a sea rose, from predators, the Spanish dancer deposits with its eggs some of the toxins that it produces for its own defense. Once hatched, the free-swimming larvae join the plankton until they mature. With a life-span of about a year, they grow rapidly, settling on a suitable food source when they are ready to change into the adult Spanish dancer form.