You know that expression about someone having a bug up their butt? Well, this little crab is known to make excursions up into the butts of sea cucumbers. That’s right folks, it just clambers right up in there.
It is a wee little crab – about half an inch across max, and it would be easy to miss if you weren’t looking for it. It is not at all unusual to see divers in the know shine their flashlights up the butts of cucumbers to see if they can spot one of these little fellers lurking in the shadows, and I’ve seen photographers camp out over a cucumber’s bum end to try to get the money shot of one of these guys in the hole.
This crab was spotted on an Indonesian night dive as it was out, circumnavigating the anus of cucumber. We’d watch it crawl up the butt of this crazy patterned cuke, and then the cuke would expel it, with a surprising amount of force – you might even call it an awoosh ;^) And then it would crawl right back up in there again. The guide and I shared a few giggles as we watched this sequence happen several times.