Mark,
This is true. In fact all living things are opportunists and their success
often hinges on their opportunism. Man is of course the greatest example,
but throughout the US the coyote has succeeded despite really heavy
persecution by man because it is an opportunist extrodinaire. In the
mollusc world the octopus pretty much fits that bill. As for a shelled
example (other than Alta's Cypraea cervus) I'm a bit stuck.
How is the simpler life treating you?
Tom