The sea bunny is one of the cutest creatures in the world. However, they’re not what you think. These little species are full of toxins. Let’s dive into the fascinating world of sea bunnies and uncover some interesting facts about their underwater lives.
Phylum: Mollusca
Class: Gastropoda
Family: Discodorididae
Genus: Jorunna
1. The sea bunny is not a bunny
Although looking like a rabbit, the sea bunny has very little in common with its land-dwelling counterpart. This adorable and captivating marine animal belongs to the species of nudibranchs, which are soft-bodied sea slugs with no shells.
Besides the appearance of the white body with black spots, these sea slugs also come in a variety of colors, including brown, yellow, orange, and even green. They are very small, with an average size of less than an inch (2.5 centimeters) in length.
These cute sea bunnies don’t have fur. The coat that you see is made up of clusters of tiny rods called caryophyllidia. These are clustered around small knobs that are sometimes black, creating the speckled pattern that is characteristic of the sea bunny.
Their ears are actually two long rhinophore antennae with tiny flaps protruding on the sides. Their eyes are located at the base of the rhinophores. The sea bunnies’ tail is their gills which are located on their backside. This is a unique feature of the dorid nudibranch group.
2. Their ‘Ears’ Are Sensory Organs
As mentioned above, the two little ‘ears’ of these bunnies are rhinophores which are their sensory organs. Although these “ears” are made of skin and nerves instead of fur, they still have the appearance of rabbit ears, thick and fuzzy.
The sensory organs aid the sea bunny in detecting chemical scents in the water, letting it locate food and possible mates. Surprisingly, sea bunnies are capable of sensing smells over remarkably long distances, despite their small size.
The antennae-like structures work in conjunction with caryophyllidia rods to help the species perceive their surroundings. The slug’s other senses are severely restricted, with their eyes only capable of discerning light and dark.
3. Habitat
The sea bunny lives in Indo-Pacific Ocean, ranging from South Africa to the central Pacific. They are found in Réunion, Tanzania, the Philippines, Papua New Guinea, and Seychelles. The black and white sea slug appears to predominantly locate in Japan’s coastal waters. These slugs, like many other animals, are thought to seek out locations with sufficient food supplies.
4. Diet
The sea bunny mainly eats sea sponges, but they also consume seagrass, algae, as well as other species like sea snails and other sea rabbit slugs.
The sea sponges contain mycalolide B, a toxin that can inhibit the proliferation of cancer cells in humans. However, the practical application of this property has been limited, and researchers are currently investigating ways to utilize mycalolide B to create efficacious drugs that prevent the spread of cancer throughout the body.
5. They are poisonous
Without a shell, sea rabbits have to find their own a defensive mechanism to protect themselves. With sea bunnies, it’s macrolide B – a highly powerful poison.
Interestingly, the ocean bunny doesn’t produce the toxin on its own but rather acquires it through its diet of sponges. While the sea bunny is immune to the toxin, its predators are not.
This effectively deters predators from attacking the sea bunny, as once they consume it, they will avoid repeating the unpleasant experience. Humans should avoid this fluffy bunny sea slug as well. Do not touch or eat it!
6. Sea Bunnies Are Hermaphrodites
The sea bunny, like the lochi, is hermaphrodites. They possess both male and female reproductive organs, meaning they can produce both eggs and sperm. However, they cannot fertilize themselves, necessitating the exchange of sperm with another sea bunny.
As the result, sea slugs play a unique dual role as both mother of their own offspring and father of other sea bunnies’ offspring. Those offspring are siblings.
Due to this ability, these rabbit sea slugs can mate with any sea bunny they run into. However, it costs them lots of energy since they have to create sperm and egg cells for their whole lives.
The bunny slugs use their highly developed sensory system to locate potential mates. After finding each other, they begin to mate. During mating, sea bunnies use their long copulatory spines to thrust into each other until the sperm exchange is complete.
The bunny of the sea has a relatively short lifespan of 3-12 months and tends to live solitary lives, making each opportunity to mate critical.
7. Threats
The sea bunny rarely faces the threat of predators due to its high toxicity. However, the primary risks to their survival are overfishing, contamination, and habitat destruction, specifically coral reef deterioration.
As many sea slug species lose their hard shell in adulthood, they are susceptible to ocean acidification and other water contaminants that can harm their soft outer shell.
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