8-13-21

I spotted this crab that seemed to be fidgeting down in the reef with saddle wrasses moving about it.

It looked like it was attacking the rock-boring urchin and in reviewing some of the images I was able to confirm this.

It was breaking off the spines.

The image above shows the crab from the other side of the hole it would move into. It was likely working on the back side of the urchin which I could not

view. However when the crab was out in front working on the urchin, wrasses would dive into the hole from this side and probably check on the progress.

If I got too close or hung down there too long, the crab would stop and move back into the hole. It had to contend with me as well as fish getting in its

face. it would work on the urchin from the side as seen in image below and I could take some shots without it seeing me or the camera.

At one point the crab had removed a piece of reef from inside and I am not sure if that exposed more of the urchin as I suspect or just gave the crab more

room to move, inside.

I have no idea if the urchin was moving during this attack or what the ultimate goal of the crab was other than breaking into the urchin for a meal. Did the

crab need to get the urchin loose and expose its mouth? I had hoped to stick around and find out.

As time marched on, it appeared that the crab was just breaking away spines at the side near the crab's hole with presumably a plan to breach the urchin's

test in that area. I still hoped to be witness to the end game but this was taking a long time!

I watched the crab work on the urchin for 40 minutes based on the time stamps on the images. It was clear that more spines had been broken off in this

time span but it did not look like the end was anywhere near so I left. Clearly it could speed up the process a bit without having to be concerned about

me.