lpetrich

This is another supposedly impossible-to-evolve thing that creationists sometimes toss out; why would a big carnivore allow some possible prey the free run of its mouth?

Cleaning symbioses sometimes happen on land, as with Egyptian crocodiles and Nile plovers, but they are most common among fish; here is a <a href="http://www.opwall.com/evolution_and_ecology_of_cleanin.htm" target="_blank">nice little article</a> on some of the work that has been done.

The favorite hypothesis for its occurrence is that the cleaned one benefits from the cleaner eating troublesome parasites like leeches. Thus, some big fish that has a tendency to ignore very small fish after it has done some eating would get cleaned by hungry small fish, thus improving its health. This can evolve further into fish signaling each other about wanting to clean or be cleaned, including full-time cleaner fish having horizontal bright-colored stripes.

So it's not as big a mystery as some seem to think.

Duvenoy

I think that cleaning is a very ancient behavior, evolving numerous times. The niche is simply too profitable for some, small species to pass up. Did the dinosaurs not have eco-parasites? Further, the Devonian, the Age of Fishes, almost surely had something similar to modern cleaners. This is all speculation on my part, of course.

Most of the marine cleaners today are wrasse and a few species of shrimp. But every now and then, there’ll be a wrasse that’ll come off as a cleaner and when the client positions it’s self, the treacherous, little rascal will take a couple of healthy nips out of it. I’m not sure if this is a separate species or just individuals that have taken on a specialized, predatory behavior. I have read that this sort of thing is bad for business and clients will tend to avoid the station after the second attack or so.

Have there ever been any studies on fresh water cleaners? I don’t recall reading anything about them. I’ll have to Google it.

The ox peckers of Africa are especially interesting, although they seem to avoid predators. Almost every picture I’ve seen of ungulates seem to have one or several of these birds scurrying over them, happily scavenging for ticks.

I wonder, what the Jurassic version of the ox pecker might have been?

d