BANTA, M.R.*; KATZMANN, J.M.; MACKESSY, S.P.; University of Northern Colorado, Greeley, CO; University of Northern Colorado, Greeley, CO; University of Northern Colorado, Greeley, CO: Evaporative water loss during ecdysis in snakes from a broad range of habitats

Snakes are found in a variety of habitats ranging from tropical rainforests to hot deserts. Due to their elongate shape, snakes have a large surface area relative to their volume (mass) and evaporative water loss from the skin may be a concern for snakes living in arid climates. In addition, snakes periodically shed their entire skin and evaporative water loss (EWL) during ecdysis is typically elevated. This study examined whole-animal evaporative water loss (respiratory and cutaneous) in 14 species of snakes from a variety of habitats ranging from very arid to tropical. Evaporative water loss rates (mg water/hr) were calculated gravimetrically by passing dry air through an air-tight chamber holding the snake and then measuring the weight gain in tubes of anhydrous calcium sulfate located downstream from the chamber. Measurements were taken daily for 3-5 days before and 3-5 days after shedding as well as during a non-shedding period. The surface area of each snake was calculated geometrically and these values were used to control for body size in whole-animal EWL. For most species, EWL was higher in the days preceding and following ecdysis than during the non-shedding period. EWL was typically higher in the days just after ecdysis than in the days just before. As expected, EWL was elevated in species from more mesic environments. Evaporative water loss is a significant source of water loss to snakes and this loss is exacerbated during ecdysis. This water loss could be stressful and may affect the behavior of snakes from arid environments, but probably has a lesser impact on tropical or semi-tropical species.