By Vladimir Brezina
Ailsa’s travel-themed photo challenge this week is Purple.
What’s this??
Several times during our recent paddles through Southern Florida, we came across these large squishy creatures, brown with white spots, flapping their wings just under the water’s surface—
How is this connected with the theme of Purple, you may ask? Well, the connection was established as soon as I picked this one up out of the water. It immediately started oozing a dark purple liquid onto my sprayskirt. I hastily put it back into the water.
Actually, I was expecting this (although I wasn’t expecting the animal to be quite this trigger-happy). For this was an Aplysia, a sea-slug commonly known as a sea hare—and, as it happens, one of the experimental animals that we work with in the lab (although we work with a slightly different species). So I am very familiar with its defensive mechanisms. Rather like squid, a disturbed Aplysia releases, along with other secretions, a cloud of defensive ink.
This ink is deep purple—perhaps the most intense purple color I have ever seen. No wonder that such ink (from a different species of mollusc) was in antiquity the basis of a much-prized dye, Tyrian or Imperial Purple.
I don’t have a photo that does the color of the ink justice, so here’s one by another photographer that begins to give some idea—
For much more about Aplysia and its ink, including a video of the ink release, see here.
Vladimir Brezina (RIP) 
Johna Till Johnson
Wind Against Current 
Very well captured – by the way, a lovely hat… :D
LikeLike
Stylish, isn’t it? And surprisingly practical :-)
LikeLike
So fascinating ! Thanks for sharing. What a surprise I am sure to pick one if these up!
LikeLike
Many marine creatures have a bit of a surprise waiting for you if you pick them up :-)
LikeLike
Perhaps a reminder to humans. :)
LikeLike
Hehe… Aplysia is the Greek word of ”unwashed” (from aplytos – άπλυτος). I imagine that’s how the guys who first discovered it ended up after the creature released a cloud of ink on them – unwashed! :-)
LikeLike
I didn’t know that etymology—thank you! Apparently that is the correct etymology of the name (not that I doubted you, but it might have been a mistake or corruption of something else, as quite often happens with zoological names). And it looks like Linnaeus himself might have been responsible :-)
LikeLike
I just learned something new. Thank you. :)
LikeLike
You are most welcome! I try to add a bit extra to these photo challenges if I can :-)
LikeLike
Living here on the Gulf Coast and never even heard of this! The video is quite fascinating–this whole post is quite fascinating! Always learning something new. Thanks so much.
LikeLike
We saw just a few of them, swimming. And a fellow paddler who has worked as a guide in the Everglades said he never saw any until this year, when he saw them washed up on the beach every 50 yards… So they are easy to miss for years—until one year when you can’t help seeing them everywhere you go :-)
LikeLike
I wondered if this was related to the squid. Fascinating stuff.
LikeLike
Both molluscs… but squid is edible and Aplysia is not all that edible ;-)
LikeLike
It really is a beautiful purple ooze isn’t is? Such an innocuous looking creature too! Is it poisonous ?
LikeLike
Not poisonous, really ;-)
(Seriously: it may cause some mild skin irritation, especially after long exposure, e.g., when working with these slugs in the lab. So they are generally benign. But that’s just these species—you don’t want to assume that all sea-slugs are so benign.)
LikeLike
looks fun!
LikeLike
:-)
LikeLike
Fascinating post – I’ve only ever seen sea slugs on TV and in aquariums. One of the early episodes of David Attenborough’s Life on Earth has some great video of them swimming.
LikeLike
The Aplysia species we encountered in Florida (probably A. brasiliana) swims, but that’s a bit unusual for Aplysia. Most Aplysia species, including A. californica, the species we work with in the lab, don’t swim.
But actually Aplysia are among the most drab of the sea slugs. Many other sea-slugs, in particular the Nudibranchs, are vividly colored, with spots and stripes of glowing neon blue, yellow, orange… And of course they are the slugs that usually appear on TV shows :-)
LikeLike
Is this the stuff that was used to dye the togas of Roman nobility purple? And Johna, that is a very fine hat.
LikeLike
I see you already answered this question. I missed it first time through.
LikeLike
And yes, it is a very fine hat. Johna loves it! :-)
LikeLike
It is interesting to see the different ways in which creatures defend themselves.
LikeLike
It is indeed! Although it’s not entirely clear how effective the Aplysia‘s ink is as a defense mechanism…
LikeLike
Ich wünsche <3 einen schönen Dienstag Nachmittag ;-)
LikeLike
And to you too! :-)
LikeLike
very interesting! its amazing how sea creatures defend themselves. i never heard of aplysia until now. thanks for sharing. :)
LikeLike
You are most welcome! Now that you know about them, you’ll start seeing them everywhere… :-)
LikeLike
so interesting!…not something I would see in my little world…thanks!
LikeLike
You are most welcome!! :-)
LikeLike
So that’s the source of Tyrian purple! Who knew? You guys, obviously! Thanks for the lesson.
LikeLike
Tyrian Purple is hard to get anywhere these days, unfortunately ;-)
LikeLike
It’s a ninja slug! It disappears while the predator’s vision is obscured by the ink just like a ninja throws a smoke bomb to give him enough time to escape from the enemy. ;-)
LikeLike
It’s so nice of you to try to compare a slug (and they really are very sluggish) to a ninja, but it doesn’t quite work ;-)
LikeLike
Hmmm…it all depends on how slow the predator may be. ;)
LikeLike
The predator (for example, lobster) is much faster than the slug (most animals are!), so the slug has to have a Plan B :-)
LikeLike
“Carpe Diem” should be the motto of slugs so they get the most out of each day they are alive. Who would’ve thought we’d learn life lessons from slugs! haha
LikeLike
I think most animals behave that way—it’s just humans who procrastinate :-)
LikeLike
True…
That’s why it’s great to have dogs. They’re great reminders to seize the day! :)
LikeLike
This is so interesting.
LikeLike
So glad—thank you!!
LikeLike
What an awesome creature!
LikeLike
Most creatures are, once you get to know them :-)
LikeLike