Precipitation patterns and hydration status of a unique insular snake population.

Abstract

Water is essential to survival, and thus invasion of habitats having limitations of water necessitates adaptations to maintain water balance. Climate change is expected to alter precipitation patterns worldwide. A unique population of Florida cottonmouth, Agkistrodon conanti, inhabits Seahorse Key (SHK) near coastal Levy County, Florida where they are entirely terrestrial, scavenge fish carrion, and are without permanent sources of fresh water. Insofar as cottonmouths are generally associated with freshwater habitats, this insular population of snakes is likely to exhibit adaptations for living with limited resources, especially water. Our objective is to measure the hydration status in free‐ranging snakes to better understand the possible stresses related to dehydration. We hypothesize that hydration status of cottonmouths on SHK will follow patterns of precipitation. We tested dehydration and drinking behavior of cottonmouth snakes inhabiting SHK from 2001–2017. Snakes were captured and tested for thirst immediately following capture. They were provided access to fresh water for at least 12 hours while we noted drinking and weighed snakes before and after. Mass gains reflected drinking and therefore hydration status. These data were compared to satellite data for date of last rainfall event (peak >2.5 mm/hr) preceding capture (NASA TRMM & GPM). The percentage of captured cottonmouths found to drink was found to increase with an increase in the number of days since a rainfall event. Results support the prediction that hydration status of cottonmouths on SHK correlates with rainfall patterns, suggesting that snakes rely on periodic rainfall to remain hydrated. Insular cottonmouth populations are of conservation concern as annual precipitation rates have declined over the past century and may continue to decline due to climate change.Support or Funding InformationU.S. Fish & Wildlife Service, Sigma Xi, Chicago Herpetological Society, & SSARThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.