Meeting Abstract
42.2 Monday, Jan. 5 A Comparative Analysis of Evaporative Water Loss in Mammals VAN SANT, MJ*; OUFIERO, CE; HAMMOND, KA; Univ. of California, Riverside; Univ. of California, Riverside; Univ. of California, Riverside mvans001@ucr.edu
Organisms must acquire sufficient water and energy from the environment to maintain cellular function and support maintenance, growth and reproduction. Water is easily lost across body surfaces and in waste products. Terrestrial environments are the most challenging environments for maintaining water balance with deserts, in particular, being extremely challenging. Animals living in deserts face desiccating conditions and low water availability. Despite these challenges, many species of mammals thrive in deserts. Thermoregulation may be difficult for mammals living in deserts where environmental temperatures are often higher than body temperature and water must be lost for thermoregulation. Evaporation of water from the respiratory tract and skin often constitute the greatest sources of water loss for terrestrial mammals. Hence, it is likely that natural selection has provided terrestrial species mechanisms to reduce total evaporative water loss (TEWL) within the thermal neutral zone, especially in species exposed to highly desiccating conditions. We collected mean values of TEWL from the literature for 127 species of mammals ranging from 8 g to 3570 kg. We compared rates of TEWL to determine if mammals living in deserts have lower rates of TEWL than mammals living in more mesic conditions. Preliminary analysis with conventional statistics suggests that desert species do have lower rates of TEWL than mesic species. Due to evolutionary relatedness datasets containing values for related species cannot be considered independent and identically assorted. We corrected for phylogenetic relationships by using standardized phylogenetic independent contrasts as well as using a phylogenetically generalized least squares approach. Results of the phylogenetically corrected statistics will be discussed and compared with results from the conventional statistics.
