My pet tarantulas used to molt like this: their top (“cephalothorax”) would pop open like a tank turret, and the animal would slide itself out. It’s marvelous!
Can anyone identify the crab?
Outa here!
December 23, 2013 • 12:06 pm
Why Evolution is True is a blog written by Jerry Coyne, centered on evolution and biology but also dealing with diverse topics like politics, culture, and cats.
Looks like a king crab to me… Pacific. But I’m no biologist. And I’m biased (former Alaskan), so maybe everything looks like a king crab.
I saw it elsewhere identified as a Japanese spider crab.
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Aha… I never recognized it as such. Largest arthropod, eh? I think that’s right… now I see white banding on the legs, which kings definitely don’t have.
The claws are also pretty small for a king.
Damn. I’d better just stick to my specialty: identifying pubic crabs.
Species name?
Delicious when properly cooked? 🙂
It looks like the shell is moving even after the crab has gotten out. Weird…
It’s a stop motion video with the shell over an aquarium water inlet pipe (to the left).
If only we had this option. Think of all the unemployed dermatologists.
I was thinking the same thing. Plus, you could leave your old skin sitting in your office so it looked like you were working while real you went out for the day. Or, you could put moulted you in the passenger seat of your car & drive in the HOV lanes!
This would also instigate an epidemic of Capgrass Syndrome and a necessary remake of Escape from Alcatraz.
That is definitely something that would appeal to the character of Wally in Dilbert comic.
I could see it as a dream or fantasy Wally would have. If you see it in a forth coming Dilbert, you’ll know I thought of it first! 😉
Looks very much like a spider crab. The legs look a little too short to be the Japanese spider crab (Macrocheira kaempferi), so I’d say that it’s a European spider crab (Maja squinado).
I think it is a spider crab. Look at this one, named crabzilla!
It’s a young Japanese spider crab. The front limbs will grow longer as it gets older.
The giveaways are the horns in the front between its eyes and the distinctive white spots on the orange legs.
We have two of these currently at the Sea Life Aquarium where I work in Southern California.
Weird. Just plain weird and amazing.
The shit that biological systems can do. Wow.
It shames physicists, engineers, and chemists: evolution does all three all the time for a very, very long time.
Oh, yeah … that’s George. He does this at parties. I wouldn’t give him the attention.
How do they get the legs out?
Carefully?
Starting on the left, and with each limb in turn, they push the first left leg in, then pull it out, in-out, in-out, then shake it all about.
+1
Is it okay if I admit that that gives me a serious case of the willies?
And I don’t mean the free kind, either….
b&
Yeah it gave me the wiggins. It’s the legs.
A good metaphor for leaving religion:
Shed that constraining shell and live free!
Right on!
What impresses me most about this is how much bigger the crab is immediately upon emerging – the same thing happens with insects (both arthropods of course.) It just doesn’t seem right.
A friend of mine liked exotic species in her saltwater aquarium, and got her first crab some time back. She was hugely disappointed to find it dead on the bottom of the tank within a few weeks, and tearfully buried it in the backyard – and naturally, quite startled to see it in the tank again the next day. I was trying to contain my snickering as she related this over the phone…
Oh see – if we shed our skins the would make great dopplegängers!
I mean doppelgängers. The other word was a moult of this one. 😀
All of my tarantulas (I am down to one now) when molting laid onto their back, and then pushed the old skin up and away. Totally different from that crab.
Similar in every respect but orientation, I’d say.
(I’m down to 3 tarantulas. 😀 )
One of the most important of fossil arthropod groups, the Trilobata, obviously had to perform ecdysis – moulting – too. Most would split open along a line across the cephalon and glabellae (“cheeks”) called the facial suture, Consequently it is very common to find what appears to be a complete trilobite, but on preparation, you find that the anterior portion of one or both cheeks is missing, suggesting that this is a cast exoskeleton rather than a body fossil.
While most palaeontologists would give their firstborn for a reincarnated dinosaur (sensu Owen, not Bakker), there are a lot who would give their eyeteeth for a tank full of trilobites.
What helps the crab escape is that the new shell is soft, so the muscles can contract rhythmically, ‘crawling’ each leg out. There are also large delicate gills at the base of each leg (tucked under the carapace). These also molt their cuticle, but I think these molt by getting turned inside out.
The interface between the old and new cuticle is filled with a ‘molting fluid’ that partially digests the inside of the old shell, and provides a bit of lubrication. Just when the crab escapes you can see a milky puff of fluid. That might be the molting fluid, but I am not sure.
And there I was thinking that Baby Jesus materialised inside each leg in turn and pused the feet out from the end!