Notice that the article says it takes 15 to 20 years
to dig that size hole. How long it takes depends on
a lot of factors. Pencil urchins do the most digging.

Wayne Sallee
Wayne's Pets


Pszemol wrote on 2/25/2007 2:09 PM:
"Wayne Sallee" wrote in message
k.net...
I would not count on any urchin not eating rock, though some eat it
more than others. Live rock + urchin = Live sand :-)

I had maybe 3 tuxedo urchins over the years and
have not noticed them eating rocks... They eat
sometimes surface layers of coraline algae, but
not rocks.

I was talking about rock boring urchins as they
literaly bore a hole in the rock for themselves
and sit in the hole they made grazing on the
algae on the hole surface. This is their way of
avoiding predation: they are protected with rock.

Check this out: http://www.jal-foundation.or.jp/html/coral/lesson4.htm