The Jorunna parva, commonly known as the sea bunny, is a small marine gastropod mollusk that has captured widespread attention due to its distinctive appearance. This dorid nudibranch, a type of shell-less sea slug, typically measures about 2 to 3 centimeters in length. Its body is covered in small, fleshy projections called papillae, which give it a soft, “fluffy” texture resembling a rabbit’s fur. Two prominent structures on its head, known as rhinophores, further enhance its bunny-like resemblance, looking much like rabbit ears. This unique and endearing aesthetic contributed to its significant popularity on social media platforms, particularly in Japan around 2015.
Their Exclusive Diet
Sea bunnies exhibit a highly specialized diet, primarily consuming specific types of sponges. Jorunna parva feeds on toxic sponges, particularly those belonging to the family Chalinidae. These sponges contain compounds that other marine organisms might find harmful. Their feeding is focused on these particular sponge species found within their marine habitats. This specialized diet allows them to thrive where these sponges are abundant, contributing to the marine ecosystem by helping control sponge populations.
How They Consume Their Food
Sea bunnies employ a specialized feeding apparatus to consume their sponge diet. They possess a ribbon-like structure called a radula, which functions similarly to a tongue equipped with teeth. This radula is covered in multiple rows of tiny, chitinous teeth that face backward.
The sea bunny uses this unique organ to scrape off minute particles from the surface of the sponges they feed on. This scraping action allows them to break down the sponge tissue into digestible fragments. The radula’s design, with its numerous teeth, is well-suited for processing the fibrous material of sponges.
Diet and Unique Defenses
The specialized diet of sea bunnies contributes to their defensive capabilities. As they consume toxic sponges, these nudibranchs absorb and store the sponges’ chemical compounds within their own tissues. This process, known as sequestration, allows the sea bunny to become unpalatable or even toxic to potential predators. The sequestered toxins are stored in specialized glands or cells within their skin and other body parts. When threatened, sea bunnies can release these stored chemicals, deterring attackers.
Beyond chemical deterrence, the sea bunny’s coloration, which can include shades of yellow, white, or brown, serves as a warning signal to predators, a phenomenon known as aposematism. This display advertises their toxicity, encouraging predators to avoid them. The specific pigments that give them their color can be derived from the sponges they consume. This integrated defense mechanism, combining acquired chemical toxicity with visual warning signals, is a direct consequence of their diet, protecting them in their marine environment.