Tuesday, September 23, 2008

Sea hare oozing purple goo

While I was wondering on the South Beach of Fremantle last Saturday, I found two sea hares (Aplysia species) that had been washed ashore. And both were still alive.



I saw this one first. It was about 10-12 cm in length I think.



This one was near the water's edge. Similar to the first one in size. It seemed weak and was nudged further and further towards the shore by the incoming tide. Anyway, after a while, I didn't see it on the shore anymore. So I would assume it made it back into the ocean.

I have seen sea hares a few times and put up a few posts about them before. They are amazing animals, both when they are doing their beautiful dances and when they are copulating. But when they are washed ashore and dying, they are sad to look at.


The first sea hare was pretty stressed I guess. I saw it oozing some purple ink near its "tail" (?) after a while. Yes, it was purple, as I read here.




The purple ink is used for defense, but it is also excreted when the animal is disturbed (it seems).

A group of scientists paired a sea hare and a lobster in the same aquarium and found that the sea hare could use its purple ink to confuse the predator. Some compounds in the ink appear to have an effect on the lobster's nervous system. And while the lobster was still "assuming" that it had caught the sea hare or was still trying to figure out what's happening, the sea hare would run for its life. There are three short clips of their experiments here.

5 comments:

Mosura said...

What fascinating animals.

Tsun-Thai Chai said...

They sure are.
By the way I was wondering if these sea snails could still "dance" like a ballerina if they carried a shell.

Denis Wilson said...

I remember your earlier post about chasing one of these things, when it was swimming.
Barely recognisable on the sand.
Cheers
Denis

Novablogger said...

I live in Florida and once a year we have huge numbers of those sea hares wash up on our beaches. You can always find them because they leave huge splotches of purple ink wherever they lay. My brother and I would always pick them up and skip them like rocks into the ocean. They are perfectly smooth and skip better than any rocks, and they leave purple puddles when they hit the water. It's a lot of fun.

Tsun-Thai Chai said...

Hi Novablogger,

Thanks for sharing.
By the way, your Aqua Marine Discovery blog is nice.

Chai

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