Habitat aridity and urine concentrating ability of nearctic, insectivorous bats.

Urine concentrating ability of nearctic, insectivorous bats determined from renal anatomy was significantly correlated to total annual precipitation and potential evapotranspiration to precipitation ratio of the habitat where the animal was collected. Habitat aridity measured by water input accounted for as much variation in urine concentrating ability as habitat aridity measured by both water and energy input. Habitat aridity, regardless of how it was measured, explained only 25% of the among-species variation in urine concentrating ability. Factors other than habitat aridity significantly affect the urine concentrating ability of insectivorous bats.