GENETIC DIVERGENCE AND MORPHOLOGICAL CONVERGENCE IN THE PRAIRIE DOGS, CYNOMYS GUNNISONI AND CYNOMYS LEUCURUS I. MORPHOLOGICAL AND ECOLOGICAL ANALYSES.

Abstract

Systematic and evolutionary biology is intriguing to me because its problematic nature makes it much like a game. Evolution can be compared to a horse race in which the handicapper (evolutionary biologist) tries to predict the set of events which will lead to the results at the finish line. In evolution, as in the horse race, an infinite number of events can occur before a horse reaches the finish. Some events are less likely than others and a good handicapper will use every bit of information available to him to improve his chances of predicting events and the outcome of a race. So too with the evolutionary biologist. In evolution, the most intriguing races are the ones where the long shot finishes first, that is, the unusual or anomalous result. Such a situation seemed possible when Robert Lechleitner (1969) reported that two species of prairie dogs, C. gunnisoni and C. leucurus, were hybridizing along a zone of contact approximately 50 miles in length in western Colorado. C. gunnisoni is a small, dark colored prairie dog which lives in colonies of rather low density between altitudes of six and twelve thousand feet (Lechleitner, 1969). Its behavioral organization is relatively simple and colonial cohesion is primarily based on the single syllable alarm bark to warn of predators (Fitzgerald and Lech-