Effects of Latitude, Season, Elevation, and Microhabitat on Field Body Temperatures of Neotropical and Temperate Zone Salamanders

We analyzed field body temperatures of neotropical salamanders (Feder et at. 1982b) to examine existing generalizations about salamander thermal ecology, which have been based almost entirely upon data for temperate zone species. Our findings can be summarized as follows: 1) Behavioral thermoregulation in the field is evidently uncommon among the vast majority of tropical and temperate salamander species. Body temperatures of tropical salamanders closely parallel seasonal and altitudinal changes in the thermal environment. 2) Body temperatures of salamanders show a complex relationship with latitude. Temperate zone species experience lower minimum temperatures than neotropical salmanders, but there are no consistent latitudinal trends in maximum body temperatures. Tropical plethodontid and ambystomatids show similar rates of decline in mean body temperature with increasing elevation, but ambystomatid temperatures are significantly warmer than plethodontid temperatures at the same elevation. 3) Variation in body temperature is greater seasonally for temperate salamanders than tropical salamanders. At a given time or locality, however, variation in field body temperature among members of a population is similar for tropical and temperate salamanders. 4) Interspecific thermal differences are not evident in sympatric species of tropical salamanders, and therefore may not serve as a means of segregation in tropical salamander communities. These latitudinal and phylogenetic differences in thermal ecology correspond to aspects of the morphology, life history, energetics, and physiological capacities of salamanders.