Marine self defence: sea hare or sea slug releases ink when threatened

Not selected for Google Earth or Google Maps [?]

Comments (7)

jeff_msn123 on July 5, 2008


What is it? Could you please explain. Thank you

Cheers, Jeff

Ian Stehbens on July 5, 2008

Hi Jeff,

This is a shell-less mollusc or nudibranch which is commonly referred to as a sea slug. It is soft, rubbery creature and these were about 10cm in length. There were millions of them on the reef flats and pools on this particular coast of 'Eua, Tonga



jeff_msn123 on July 5, 2008


Thank you for the details. How it relates to Self defence?

regards, Jeff

Ian Stehbens on July 8, 2008

I am not sure, Jeff, but I presume that the chemical may be chemically unattractive to predators, and in view of the strong colour it may be a visual distraction which averts attention to the nudibranch. If you happen to find out more let me know, please.


jeff_msn123 on July 8, 2008


I see now. Thank you

Cheers, Jeff

©Toodleberry on July 9, 2008

Wow!!! I thought this was a cave painting, then dyed hair. Now I see. Nobody's asked you this yet: is it edible?


Ian Stehbens on July 10, 2008

Dear Friends,

I think I may be wrong. While we know this creature as a sea slug, it seems on further checking that both nudibranch and sea hares are generally referred to as sea slugs. With no authority available to me, I suspect now that this is actually a sea hare. Its red inking behaviour is characteristic of sea hares, but I do not know enough about nudibranches.

I understand that the inking is most likely a defence, and that it is distasteful and toxic to some other creatures. Dogs are known to have died from eating sea hares. Fish on the other hand don't seem to be affected by its presence in the water, for those kept in aquarium with fish seem to cohabit the same confined space ok.

Should any reader provide identification or be knowledgeable about such things, I would appreciate your comment.


Sign up to comment. Sign in if you already did it.

Photo details

  • Uploaded on July 5, 2008
  • © All Rights Reserved
    by Ian Stehbens