Filial cannibalism leads to chronic nest failure of eastern hellbender salamanders (Cryptobranchus alleganienesis)

These data and code support the results in our accompanying manuscript. In species that provide parental care, parents will sometimes cannibalize their own young. Here, we quantified the frequency of whole-clutch filial cannibalism in a species of giant salamander (eastern hellbender; Cryptobranchus alleganienesis) that has experienced precipitous population declines with unknown causes. We used underwater, artificial nesting shelters deployed across a gradient of upstream forest cover to assess the fates of 182 nests at 10 sites over 8 years. We found strong evidence that nest failure rates increased at sites with low riparian forest cover in the upstream catchment. At several sites, reproductive failure was 100%, mainly due to cannibalism by the caring male. The high incidence of filial cannibalism at degraded sites was not explained by evolutionary hypotheses for filial cannibalism based on adult body condition or low reproductive value of clutches. Instead, larger clutches at degraded sites were most vulnerable to cannibalism.  We hypothesize that high frequencies of filial cannibalism of large clutches in areas with low forest cover could be related to changes in water chemistry or siltation that influence parental physiology or that reduce viability of eggs. Importantly, our results identify a possible mechanism contributing to population declines and observed geriatric age structure in this imperiled species.