Water relations of an insular pit viper [RESEARCH ARTICLE]

Mark R. Sandfoss and Harvey B. Lillywhite Colonization of novel habitats often requires plasticity or adaptation to local conditions. There is a critical need to maintain hydration in terrestrial environments having limited water. Atypical populations of Florida cottonmouth snakes, Agkistrodon conanti, inhabit continental islands with no permanent sources of fresh water. Here, we report investigations related to how these insular snakes maintain water balance considering the mainland conspecifics are semi-aquatic and typically associate with freshwater mesic habitats. We tested three hypotheses related to water relations of insular populations of cottonmouth snakes compared with those on the mainland. (1) Voluntary drinking of fresh water in free-ranging insular snakes should reflect a relationship to recency of rainfall more strongly than in mainland snakes. (2) Insular snakes will tolerate greater dehydration before drinking than will mainland snakes. (3) Insular snakes will avoid drinking seawater more strongly than will those from the mainland. Between 2001 and 2018, we quantitatively estimated the hydration status of 337 individual cottonmouth snakes from insular populations and 30 cottonmouth snakes from mainland Florida, as judged by the tendency of wild-caught snakes to drink fresh water immediately following capture. We found that insular cottonmouth snakes had a higher incidence of dehydration than did mainland cottonmouth snakes (64% versus 23%), and the hydration...
Source: Journal of Experimental Biology - Category: Biology Authors: Tags: RESEARCH ARTICLE Source Type: research