# Sea Bunny (*Jorunna parva*)

> The sea bunny (Jorunna parva) is a tiny sea slug, a type of nudibranch, that grows to just 1 to 2.5 cm long. It lives on shallow reefs and rocky seabeds across the western Pacific and Indian Oceans, where it crawls slowly over the bottom feeding on sponges. Its fuzzy black-speckled body and two upright rhinophores give it an uncanny resemblance to a miniature rabbit. Most live only about a year.

- **Category:** Invertebrate
- **Conservation status (IUCN):** Least Concern
- **Range:** Shallow reefs and rocky seabeds in the western Pacific and Indian Oceans, including Japan and the Philippines.
- **Canonical page:** https://globalanimalguide.org/animals/sea-bunny/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Mollusca
- **Class:** Gastropoda
- **Order:** Nudibranchia
- **Family:** Discodorididae
- **Genus:** Jorunna

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Jorunna parva |
| Diet | Carnivore (sponges) |
| Habitat | Shallow reefs and rocky seabeds |
| Lifespan | Around 1 year (typical of nudibranchs) |
| Length | Usually 1–2.5 cm (under 1 in) |
| Range | Western Pacific and Indian Oceans |
| Conservation status | Least Concern |

## What the sea bunny actually is

Despite the cute nickname, the sea bunny is not a mammal but a nudibranch, a shell-less marine snail known as a sea slug. It belongs to the dorid group of nudibranchs and rarely exceeds 2.5 cm in length. The 'ears' that make it look rabbit-like are actually rhinophores, sensory organs it uses to detect chemicals in the water. The 'fur' is a dense covering of tiny bristle-like structures called caryophyllidia scattered across its back.

## How it moves and senses the world

The sea bunny has no fins and cannot swim in any meaningful sense; it crawls slowly along the seabed on a muscular foot, gliding over sponges and rock at a fraction of a centimetre per second. Its two rhinophores work like chemical antennae, sampling the water to locate food and potential mates. A feathery gill plume sits toward the rear of the body and handles breathing. Because it moves so little and so slowly, it relies on chemical defences rather than speed to survive.

## Diet and chemical defence

Sea bunnies are carnivores that graze almost exclusively on sponges. As they feed, they absorb toxic compounds from their prey and store these chemicals in their own tissues, making themselves distasteful or poisonous to would-be predators. Their bright colouring is a warning signal advertising that toxicity. This strategy of borrowing defences from their food is common across nudibranchs.

## Where it lives

Jorunna parva is found in warm, shallow waters of the western Pacific and Indian Oceans, including reefs around Japan, the Philippines, and other parts of the Indo-Pacific. It favours shallow reefs and rocky seabeds where sponges are plentiful. Divers usually spot it in the same habitats where its food grows, tucked among rocks and coral rubble. It is a bottom-dweller and does not venture into open water.

## Reproduction and short life

Like nearly all nudibranchs, sea bunnies are hermaphrodites, meaning each individual carries both male and female organs. When two meet, they can fertilise one another and both may lay eggs, which are deposited in delicate coiled ribbons on the seabed. Their lifespan is short, typically around a year, which is normal for small nudibranchs. This quick turnover means populations depend on frequent breeding.

## How it became internet famous

The sea bunny shot to viral fame in 2015 when photographs circulated online showing its rabbit-like face and fuzzy body. Social media users were charmed by an animal that looked like a tiny bunny hopping across the reef, even though it is a slug that barely moves. That surge of attention introduced millions of people to nudibranchs for the first time. It remains listed as Least Concern and faces no notable conservation threat.

## Frequently asked questions

### Is a sea bunny a real animal?

Yes. The sea bunny is a genuine marine animal, a nudibranch or sea slug with the scientific name Jorunna parva. It is not related to actual rabbits; the resemblance comes from its fuzzy body and two upright rhinophores that look like ears.

### How big is a sea bunny?

Sea bunnies are tiny, usually just 1 to 2.5 cm long, smaller than a coin. They weigh only a fraction of a gram, so they are easy to overlook on a reef.

### What do sea bunnies eat?

Sea bunnies are carnivores that feed almost entirely on sponges. As they eat, they store toxic chemicals from the sponges in their own bodies, which makes them poisonous to predators.

### Are sea bunnies poisonous to touch?

Sea bunnies carry toxins absorbed from the sponges they eat, which serve as a defence against predators. They are not aggressive and pose little risk if left undisturbed, but like all nudibranchs they are delicate and best observed rather than handled.

### How long do sea bunnies live?

Sea bunnies have a very short life, typically around one year. This brief lifespan is normal for small nudibranchs, which grow, breed, and die within a single season or two.

### Where do sea bunnies live?

They live on shallow reefs and rocky seabeds in the warm waters of the western Pacific and Indian Oceans, including areas around Japan and the Philippines. They stay on the bottom near the sponges they feed on.

## Sources

- [IUCN Red List — Jorunna parva.](https://www.iucnredlist.org/search?query=Jorunna%20parva&searchType=species)
- [Animal Diversity Web — Jorunna parva. University of Michigan Museum of Zoology.](https://animaldiversity.org/accounts/Jorunna_parva/)
- [Wikipedia — Sea Bunny.](https://en.wikipedia.org/wiki/Jorunna_parva)

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Source: Global Animal Guide (https://globalanimalguide.org/animals/sea-bunny/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.