The internet has popularized the “sea bunny,” a tiny marine organism resembling a fluffy rabbit, which has captured widespread attention and is often shared across social media platforms. While its common name suggests a cuddly mammal, the sea bunny is, in fact, a distinct type of sea slug.
What Exactly is a Sea Bunny?
Despite its charming nickname, the sea bunny is not a mammal but a species of sea slug, specifically a dorid nudibranch. Its scientific name is Jorunna parva. This creature gained viral popularity in 2015, particularly on Twitter in Japan, due to its striking resemblance to a rabbit. The “bunny” nickname comes from its two prominent head appendages that look like ears and a posterior cluster that resembles a tail. Its small size, typically less than an inch (2.5 cm) long.
Distinctive Features and Function
The features that give the sea bunny its rabbit-like appearance serve specific biological functions. The “ears” are actually chemosensory organs called rhinophores. These fuzzy, antenna-like structures help the sea bunny detect chemicals in the water, essential for navigation, locating food sources, and finding potential mates. The “tail” is its branchial plume, a cluster of external gills used for respiration, allowing the slug to absorb oxygen from the surrounding water.
The sea bunny’s “furry” texture is created by numerous small, rod-like projections called caryophyllidia that cover its body. These papillae also play a sensory role, helping the creature perceive its environment. While often depicted as white or yellowish with black spots, sea bunnies can also display other color variations, including orange, brown, and rarely green. This coloration can sometimes serve as a warning to predators, indicating its toxicity.
Habitat and Behavior
Jorunna parva is primarily found in the Indo-Pacific region, including waters off Japan, the Philippines, Indonesia, and other areas of the Indian Ocean, extending from South Africa to the Central Pacific. These sea slugs prefer shallow, tropical waters and are benthic, meaning they live on or near the seafloor, often on rocky substrates or marine vegetation. They move slowly along the ocean floor using a muscular foot.
Sea bunnies are carnivorous, primarily feeding on sponges, particularly those from the family Chalinidae. Their diet is directly linked to their defense mechanism; they absorb and store toxins from the sponges they consume within their skin and rods. This makes them unpalatable and toxic to most predators, deterring potential threats.