EVIDENCE FOR EMPATHY IN PAIR BONDING POISON FROGS

Abstract

AbstractEmpathy is critical to individual and societal wellbeing in humans. More than a century ago, Charles Darwin hypothesized that the empathy-like phenotype is a phylogenetically widespread phenomenon. This idea remains contentious, partly due to few investigations among non-mammalian vertebrates. We provide evidence for Darwin’s hypothesis by discovering key empathetic features, emotional contagion and ingroup bias, in pair bonding Ranitomeya imitator (Mimetic) poison frogs. We found that the corticosterone level of males appears to positively correlate with female partners across various conditions, including cohabitation and during experimental manipulation. This response is selective towards female partners relative to familiarized female non-partners and is irrespective of partnership longevity or lifetime reproductive output. However, hormonal state matching is not reflected behaviorally, indicating that behavioral state matching can be an unreliable proxy for emotional contagion. These results constitute the first evidence for emotional contagion in an amphibian. Together with findings in other taxa, they suggest empathy is evolutionarily widespread among social vertebrates.