Metabolic Adaptation to Climate and Distribution of the Raccoon Procyon Lotor and Other Procyonidae.

Mugaas, J. N., J. Seidensticker, and K. Mahlke-Johnson. Metabolic Adaptation to Climate and Distribution of the Raccoon Procyon lotor and Other Procyonidae. Smithsonian Contributions to Zoology, number 542, 34 pages, 8 figures, 12 tables, 1993.—Although the family Procyonidae is largely a Neotropical group, the North American raccoon, Procyon lotor, is more versatile in its use of climate, and it is found in nearly every habitat from Panama to 60°N in Canada. We hypothesized that most contemporary procyonids have remained in tropic and subtropic climates because they have retained the metabolic characteristics of their warm-adapted ancestors, whereas Procyon lotor evolved a different set of adaptations that have enabled it to generalize its use of habitats and climates. To test this hypothesis we compared Procyon lotor with several other procyonids (Bassariscus astutus, Nasua nasua, Nasua narica, Procyon cancrivorus, and Potos flavus) with respect to (1) basal metabolic rate (Ḣb), (2) minimum wet thermal conductance (Cmw), (3) diversity of diet (Dd), (4) intrinsic rate of natural increase (rmax), and, where possible, (5) capacity for evaporative cooling (Ec). We measured basal and thermoregulatory metabolism, evaporative water loss, and body temperature of both sexes of Procyon lotor from north central Virginia, in summer and winter. Metabolic data for other procyonids were from literature, as were dietary and reproductive data for all species.