The Lion’s Mane Nudibranch Sea Slug, Melibe leonina | The Critter Corner

Like a transparent, watermelon-Jolly-Rancher-scented Stegosaurus with a Venus flytrap for a face, the lion’s mane nudibranch sea slug (Melibe leonina) is a lot of things—including one of the kelp forest’s most magical critters! __ Animal Facts Scientific Name: Melibe leonina Animal Type Invertebrates Diet copepods, ostracods, and other small planktonic animals Size to 4 inches (100 mm) Relatives sea hares, sea lemons, Hopkin’s rose; Order: Nudibranchia; Phylum: Mollusca Habitat Kelp Forest Range Alaska to the Gulf of California Natural History This melibe is like no other nudibranch (sea slug). Instead of a rasping tongue, it sports a unique oral hood that captures small planktonic animals. To feed, a melibe firmly attaches itself to a kelp blade and then sweeps its raised hood downward or to the side. When food lands on the lower surface of the hood, the melibe sweeps together the two sides of the hood, and its fringing tentacles lock in the prey. The hood contracts to force the captured food into the melibe’s mouth. Melibe and the giant kelp plants they live on have matching colors—yellowish brown to olive green. Melibe are hermaphrodites (they have both male and female sexual organs), and fertilization is internal. The animal can lay as many as 30,000 eggs, which are enclosed in a long, gelatinous ribbon. Conservation This unique and amazing animal is neither collected nor hunted, but its existence depends on healthy kelp forests and other seaweed beds. Sludge and other pollutants smother tiny kelp plants during their microscopic stage. As stewards of the ocean, it’s crucial that people around the world properly dispose of wastes, chemicals, solvent and paints that can harm nearshore habitats. Cool Facts During the warmer months, huge numbers of melibe appear in kelp canopies and eelgrass beds. Although they prefer to stay attached to a surface, melibe do swim when dislodged or if they’re approached by a kelp crab—then they close their hood to reduce drag. Most predators avoid the noxious secretions of nudibranchs, but the kelp crab is an exception. The noxious secretions of the melibe smell like watermelon, according to aquarists who clean the melibe exhibit.