ABSTRACT
Theories are the skeletons that give reason to facts, allowing a complex body of data to be fleshed into some definitive and usable form. Recent interest in facts about the biotas of islands has given rise to much theory and has stimulated a great deal of thought. At times, the facts involving insular biotas are merely aggregations of numbers, or at best, rude categorizations of some aspects of niches; thus, theories derived from such “facts” may be open to question. In view of the high stakes–i.e., survival or extinction–involving the ichthyofauna of the Colorado River Basin, a careful review of facts as well as theories is clearly in order.
