Sea bunny | Super Interesting Facts You Must Know

Sea bunny is a super cute sea slug belongs to a wild group of mollusks. A Japanese diving team released a sea bunny’s video in 2015 and since then most aquarists try to find them.

I know you must have a lot of questions about sea bunnies. You do not have to read a lot to find the answers. I have done it for you. I read lot and here I present what I found about sea bunnies.

What is a sea bunny? 

First I found their scientific name as Jorunna parva. Moreover, scientists categorize these animals under the group called Nudibranch

Nudibranchs are a shell-less gastropod Molluscan that belongs to the family Discodorididae.

Sea bunny is a little creature that has a fluffy look. Also, they have wiggly little ears, tails, and black color dots that cover the whole body.

They have a white, yellow, or orange body with black spots. Their outer cover looks like fur . But they do not have actual fur. Those are the structures that contain sensory organs. 

Most predators stay away from them. Because they are incredibly toxic. This little creature can grow around one inch in the wild. The lifespan of a sea bunny is relatively short. They live for several months or maximally one year.

In the wild, they are found in the Indo Pacific Ocean from South Africa to the central pacific. 

Can you have a sea bunny as a pet?

I am sure you have looked for an answer for this question in so many places. So this is the answer.

It is not recommended to have a sea bunny as a pet of your saltwater aquarium. I know this is not the answer you looked for. But there are few reasons why you should not keep them as pets.

First reason is, they are an extremely toxic slug variety. Thus, rearing them in your aquarium is not safe. 

Further, feeding Nudibranchs in the aquarium is quite difficult. They mainly eat sea sponges as a main part of their diet. Thus, you should have a method to supply sponges to them, if you wish to rear sea bunny. Sea sponges also contain toxic compounds. 

If sea bunnies’ secretions are dissolved in water, every live creature of your tank may die.  Moreover, they will get sucked into powerheads and filter systems of your tank. 

Sea bunny appearance 

Although you can not keep sea bunnies as pets it is worth knowing further about these cuties.

Sea Bunny (as the name implies) is a cute little thing that has a soft cottony appearance. Their body coat is like fur. Additionally, bunnies have different color body coats.  

They have ear-like structures on the top of their head. The posterior body of the sea bunny contains a tail-like structure. But it is not an actual tail. It is their Gill and it is used for respiratory purposes.  

Further, they have black spots on their outer body. They grab sensations from black spots and ear-like antennas. 

Sea bunnies do not have eyes. This slug is a shell-less variety. Their body size is around one inch or less than an inch.

Different color varieties

In the wild, sea bunnies have some different color varieties.

These are,

  • White color
  • Yellow color
  • Bright Orange color
  • Brown color

When comparing the above varieties, the only difference is their outer appearance. because their whole body functions and behaviors are the same.

How many types of sea bunnies are there?

Sea bunny is a member among 16 species of the Discodorididae family. Among these sea bunny species below are sea bunny’s close cousins.

Jorunna Funebris (Dotted nudibranch )

This species is known as dotted nudibranch. It is a dorid nudibranch. That means, these sea slugs are  shell-less marine gastropods that belong to Mollusca. 

 The dotted nudibranch has a fluffy look, fleshy oval body. Mostly their body colors are white.  

They are one of the largest slug varieties of the Discodorididae family. Their body size ranges from 1 to 6 centimeters wide. 

Dotted nudibranchs have black circle markings on their body. These markings are made up of black bristles called “caryophyllidia”

Dotted nudibranchs are inhabited in Indo-Pacific regions.

They are commonly found in countries such as,

  • Sri Lanka
  • Australia 
  • New Caledonia

This slug also feeds on a variety of sponges. 

 Jorunna Tomentosa

This slug species has a yellow to sandy brown color body. They have a mantle and it has a velvety look. The mantle consists of several pairs of dark brown spots. Generally, they can grow around 5.5 cm. 

This dorid nudibranch gastropod is commonly found in European waters such as:

  • Norway
  • Portugal 

They also reported in,

  • Mediterranean Sea
  • South Africa
  • Tristan da Cunha

Size of the sea bunny

Sea bunnies are cute little creatures. They can maximally grow around 1 inch (2-2.5 cm) in the wild. 

Ears, tail, and fur of sea bunny

The Sea bunny is equipped with two antenna-like “ears” and a fluffy “tail”. 

Sea bunnies have a soft cottony outer appearance. But their body coat does not cover them with actual fur. 

You can see the black spots that spread across the sea bunny’s body. These structures are called “Caryophyllidia”. 

Their furry appearance comes due to the Caryophyllidia. Those black spots also function as sensation receptors. These structures increase the body surface of the sea bunny. 

Sea bunny’s outer body has different colors like yellow, orange-brown, and white. Further, this saltwater bunny has no actual ears. They are the sensory organs. They are called “Rhinophores”.

The ear-like structure allowing them to find,

  • Foods
  • Potential mates 
  • Chemical scents in the water column

Sea bunnies have a flower-like structure on the posterior side of their body. People identify it as a tail. But it is not an actual tail. It is a gill that facilitates respiration. This little beauty does not have eyes.   

Sea bunny habitat

They are native to Indo pacific regions. But they are commonly found in the ocean of the following countries.

  • Japan
  • Philippines
  • Australia
  • Tanzania
  • Papua New Guinea
  • Seychelles 
  • Reunion 

What they eat

In the wild, they mainly eat sea sponges. Sea sponges also contain toxic and sea bunnies grab and accumulate these toxins in their body. 

Male and female of sea bunny

Sea bunny is a hermaphrodite. They have both male and female reproductive organs in the same animal. 

But they cannot fertilize their eggs by themselves. They need the sperm of another animal to fertilize their eggs.

How do sea bunnies reproduce?

In the mating process, two bunnies are attached to exchange their sperm. Because of their well-developed sensory system, they can lay their partners’ bodies.

Sea bunnies have long copulatory spines to inject sperm into the partner’s body. This long spine also ensures that they are attached till sperm exchange is done.

When they are mating, both parents exchange sperm and fertilize their eggs by using these sperm.Because of this trait, they can be a mother of their babies and a father of someone else’s babies. These both sea bunnies’ offspring are siblings. 

Behavior of sea bunny

Sea bunnies are not fast swimmers. They have very slow movements. 

Sea bunnies can identify food availability and water currents using their sensory organs. They are the animals that search for food throughout the day. They always act hungrily. Thus, they are mainly associated with the areas that have enough food.

They can find their partners also using sensory signals.  They have a good mechanism to protect from predators. If some predators try to attack them, the sea bunny sprays their toxins to protect them.

Life span

This little slug does not have a long-life span. They can live only a couple of months to a year. Because of their short life span, they have an isolated lifestyle.

Further, their extremely developed sensory system helps them to mate. Sea bunnies quickly produce their offspring before they die. That behavior helps maintain their population in the ocean.

Toxicity of sea bunny

These sea slugs are known as “dorid nudibranchs” and this variety grabs toxins compounds from their foods. Further, sea bunnies often eat sponge varieties that contain the toxin. 

Further, sea bunnies can steal stingers out from Jellyfish. Bunnies use those stingers for their defense.  

The marine predators stay away from them because sea bunnies are extremely toxic.  

Predators of sea bunny

There are extremely toxic compounds hiding with this small beauty. Therefore, predatory activities are minimal for them. If some fish try to eat them, sea bunny spray toxic to them 

If any predator bites a sea bunny, the toxic compounds will be released from the bunny’s body. Then predators will die because of the toxicity.

Do Sea bunnies live in coral reefs?

Sea bunnies are found in many marine habitats throughout the world. They inhabit up to 20 meters depth of ocean excluding marine pools and estuaries. 

Sea bunnies spend their lives primarily on the seafloor where they have sufficient food. Further, sea bunnies like to inhabit tropical waters and coral reef areas. Because coral areas are rich with sea sponges. Sea bunnies love to inhabit the places where their foods  are highly available.

Are sea slugs endangered?

Sea slugs are not categorized as endangered species. Because they are commonly found in tropical waters of the Indo Pacific region.

Credit to : Animal Fact Files
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About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.