decorator urchin?

does anybody's else urchin pick up crap on its back. is this a defense tactic?

 

It is believed this is a defense/camouflage tactic. It is also believed that their spines are a reason why Trigger's eye's are so far from their mouth.

 

I have 3 urchins in my tank...they are constantly carrying crap around. My blue tuxedo carries around polyps of coral and cheato, but so far he sticks to only carrying my xenia so I dont mind so much. Plus he is so COOL looking, his coloring is one of the neatest that I have seen. My bigger ugly white urchin is going after my zoos and carrying them around which I cant stand. But I have to laugh when he gets ahold of my crabs and snails....all you see are these legs hanging out of these shells kicking around trying to get free. I am going to have to get rid of the big ugly one as I can not tolerate him pulling off my PPE and eagle eye zoos and killing them. The third one, leaves everything alone..not sure what type he is but his needles are a lot bigger then the other two, so I assume he does not have to camoflauge himself. But they are really good algea eaters!

 

It's also a sign of a healthy urchin, we had one recently the wore a suction cup for a cap, wish I would have gotten a pic.

 

Now that would have been a sight!

 

that reminds me...my ugly white one carried an algea scrapper around for about 3 weeks. I wish I would have gotten a picture of that! It was a little plastic hand held one without a handle...it was hysterical. When I wanted to scrap the tank I would take it off him and then when I was done I would place it next to him. The next day he would have it back on the top of him again. Maybe I ought to put that back in my tank and see if he will grab that and leave my corals alone!