Two research teams suspect they've caught wild animals bluffing their own kind. The scientists know of only one other published example outside of primate antics.
When an intruder croaks, small male green frogs (Rana clamitans) drop their responding croaks extra low, like genuine big guys, say Mark A. Bee of the University of Missouri in Columbia and his colleagues. For an especially deep-voiced intruder, the little guy makes his deepest response, they report in the March-April Behavioral Ecology.
Similar moxie shows up in a study of an Afro-Asian species of fiddler crab known to take a short cut to regrowing a lost claw. Male Uca annulipes produce a substitute as long as the original but lighter and flimsier, explains Patricia R.Y. Backwell of the Smithsonian Tropical Research Institute in Balboa, Panama.