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Phylum Mollusca > Class Gastropoda > sea slugs > Order Anaspidea
Hairy sea hare
Bursatella leachii
Family Aplysiidae
updated May 2020
if you learn only 3 things about them ...
Sea hares may secrete a purple dye. But don't tease them to make them do this.
Although they can be quite large, they are well camouflaged. Watch your step!
Sea hares have very specialised diets and should not be kept in home aquariums.

Where seen? This hirsute sea hare is sometimes seen on our Northern shores among seagrasses and seaweeds. Sometimes many are seen scattered everywhere, then they are no longer seen for many months. Sometimes, several are seen gathered together, densely packed in large numbers, possibly mating? Or simply gathering around a good source of food?

Changi, May 05

Two pairs of tubular tentacles

Short triangular 'tail' edged with white bars.
Features: 6-12cm. Body long, fleshy with a short triangular tail which has white bars. It is covered with lots of flat branching finger-like projections. It has two pairs of tentacles, oral tentacles and rhinophores about the same size (you have to look carefully among the hairy bits to distinguish the tentacles). The parapodia appears to be a hole in the centre of the body, rather than 'wings' or flaps as in other large sea hares. It may come in different shades of brown, sometimes bluish, sometimes with orangey 'hairs', usually with bright blue spots which are ringed in brown. It is usually well camouflaged and blends in perfectly with among seaweeds and seagrasses. Like some other sea hares, it produces a purple ink when disturbed.

Egg mass laid by the sea hare.
Pasir Ris, JUl 19

Releases purple ink when disturbed.
Pulau Sekudu, May 04

Projections flat branching, not spiny.
Blue spots but no fine lines.
Sometimes mistaken for the Furry sea hare which has finer 'hair' and fine parallel lines. More on how to tell apart hairy slugs and snails.

What does it eat? It eats cyanobacteria, in particular, the mat-forming Lyngbya majuscula, which was formerly known as the filamentous blue-green alga Microcoleus lyngbyaceus. Apparently, Bursatella sea hares swallow large amounts of sand in the process of eating, somewhat like earthworms do.

When out of water, looks like a blob.
Changi, May 09

Pale ones sometimes seen.
Changi, May 09

Comes in a variety of shades.
Chek Jawa, Feb 07

Hairy sea hares on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Sembawang, Oct 20
Photo shared by Vincent Choo on facebook.

Coney Island, Jun 20
Photo shared by Richard Kuah on facebook.

With eggs next to it.
Pasir Ris Park, Sep 20
Photo shared by Vincent Choo on facebook.

Changi, May 11
Photo shared by Loh Kok Sheng on his blog.

Changi, Sep 10
Photo shared by Neo Mei Lin on her blog.

Pulau Ubin, Dec 09
Photo shared by James Koh on his blog.

East Coast Park, Aug 20
Photo shared by Toh Chay Hoon on facebook.

Tuas, Aug 09
Photo shared by Loh Kok Sheng on flickr.

Pulau Tekukor, May 10
Photo shared by James Koh on his blog.

Links References
  • Tan Yong How Jonathan. 31 Mar 2016. Congregation of hairy sea hares at Changi Point. Singapore Biodiversity Records 2016: 46-47
  • Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist of The Molluscs of Singapore (pdf), Raffles Museum of Biodiversity Research, National University of Singapore.
  • Debelius, Helmut, 2001. Nudibranchs and Sea Snails: Indo-Pacific Field Guide IKAN-Unterwasserachiv, Frankfurt. 321 pp.
  • Wells, Fred E. and Clayton W. Bryce. 2000. Slugs of Western Australia: A guide to the species from the Indian to West Pacific Oceans. Western Australian Museum. 184 pp.
  • Coleman, Neville. 2001. 1001 Nudibranchs: Catalogue of Indo-Pacific Sea Slugs. Neville Coleman's Underwater Geographic Pty Ltd, Australia.144pp.
  • Humann, Paul and Ned Deloach. 2010. Reef Creature Identification: Tropical Pacific New World Publications. 497pp.
  • Kuiter, Rudie H and Helmut Debelius. 2009. World Atlas of Marine Fauna. IKAN-Unterwasserachiv. 723pp.
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