Androcles and the green crab

My son and I went to Sandy Hook today to scout for our multi-class horseshoe crab trip scheduled later this month. We solved the more pressing issues (a Park Ranger will open the latrines, we'll bring the toilet paper), then meandered around the park.

Today a congregation's worth of fiddler crabs appeared to synchronously wave their claws at my son as he stared at them from a small wooden bridge, an osprey eyed us from her nest, and I felt a hermit crab tickle my hand as it made its escape. I have gone to the shore's edge thousands of times, and every time I see something unexpected.

Today's story, though, is not mine--it belongs to a U.S. Park Ranger, and he trusted me enough to share it with me.

The Sandy Hook Park Rangers regularly schedule walks along the beach. At this particular walk, only one person showed up, a woman in heels carrying a large black purse. One person is enough for a tour, so the two made their way to the shore's edge.

While the blue claw crab gets all the glory around here, the green crab occasionally shows its snippy smaller self around here. The few times I have found one, it was quick to scurry away, though one did nip me pretty good when I tried to grab it.

As the Ranger and his tourist stood by the water's edge, a green crab crept out of the bay, unusual enough. Even more remarkable, though, was what followed--the crab walked right up to the Ranger and the woman.

The Ranger stopped down to pick it up, well aware of the green crab's penchant for pinching. This one did not even try. While showing the crab to the woman, the ranger noticed that a tiny mussel was nestled in the apron (underside) of the crab. To the ranger, it appeared that the crab was in pain.

(No, I do not know how a ranger knows this--but if anyone would, a U.S. Park Ranger would.)

Using the woman's purse as the operating table and his knife as a scalpel, the ranger gently scraped at the byssal threads holding the mussel to the crab, finally freeing the crab from its tormentor.

The crab returned to the water.

We really know nothing about what other critters know. Nothing.

No, I did not make this up--and I doubt the Ranger did either.
The photo is indirectly via wikimedia,

Yes, I know, the Androcles analogy does not work well. I just like the title.