Altered behavior of neonatal northern watersnakes (Nerodia sipedon) exposed to maternally transferred mercury

Little is known about effects of maternally transferred contaminants in snakes. The purpose of this study was to evaluate sublethal effects of maternally transferred mercury (Hg) on neonatal northern watersnakes (Nerodia sipedon). We captured 31 gravid females along a historically Hg-contaminated river. Following birth, we measured litter Hg concentrations and assessed locomotor performance, foraging ability (i.e., number of prey eaten, latency to first strike, strike efficiency, and handling time), and learning (i.e., change in foraging measures over time) in their offspring (n = 609). Mercury concentrations in offspring negatively correlated with motivation to feed and strike efficiency. Over time, strike efficiency and latency to strike decreased for all snakes in the study. However, offspring from contaminated areas maintained consistently lower efficiencies than reference individuals. This study is the first to examine sublethal behavioral effects of maternally transferred contaminants in snakes and suggests that maternally transferred Hg negatively affects offspring behavior.

► Sublethal effects of maternally transferred mercury on snakes are evaluated.
► Locomotion, foraging and learning are assessed in neonates.
►  A negative relationship between mercury concentrations and motivation to feed and striking efficiency is observed.
► Individuals from contaminated areas maintain lower strike efficiencies over time.
► No adverse effects are detected on locomotion.