Experimental Studies on Habitat Preference and Thermoregulation of Bufo americanus, B. hemiophrys and B. cognatus

This paper reports on responses lo habitat and thermoregulotion exhibited by three species of toads, Bufo omericanus, B. hemiophrys and 8. cognalus, under artificial conditions. The response of the toads to sparse, medium, and dense vegetative cover was investigated by establishing artificial cover types in a sheet-metal enclosure. Each of the three species spent more time in the dense cover than i11 sparse or medium cover. A second experiment to determine if the toads would be attracted by odor to samples of mud, water, and vegetation from their respective ranges suggested that the toads moved randomly to the habitat samples. The role of temperature-regulating ability in habitat selection was evaluated by measuring deep body temperatures of the toads and surface temperature of the substrate under varying environmental conditions. The relations between body and surface temperature were significantly different for the three species as shown by analysis of covariance. 8. omericonus exhibited the most and B. cognotus the least thermoregulotion. The possible roles of these factors in causing the present distribution patterns of the three species ore considered