An area where species are living on or among rocks or stones: Chaotic though a bird petrobiont may appear, it is considered to be an organized, orderly community, where each kind of feathered animal has its own preference as to which location it will have for its nesting on the cliff.

As harsh as the conditions of life on a rocky shore may seem to a human observer, the birds obviously thrive and multiply in their petrobionts.

Mountain goats exist in their special petrobionts and have adapted to dwelling among the rocky formations as mountain climbers!