Total Eclipse of the Zoo: Animal Behavior during a Total Solar Eclipse

SIMPLE SUMMARY: A total solar eclipse is a rare but impactful meteorological event that has been historically associated with anomalous behavioral responses within animals. In this study, we compare the behaviors of 17 species (including mammals, birds, and reptiles) during a total solar eclipse at the Riverbanks Zoo in Columbia, South Carolina, USA to baseline behavioral observations collected prior to the event. Behavioral responses were classified into one or more of four categories: normal/baseline, evening, novel, and apparent anxiety. Approximately 75% of observed species exhibited a behavioral response to the eclipse, with the majority of these animals engaging in their established evening or nighttime behaviors. The next most frequent response was apparent anxiety. These observations provide new data on the behavioral impact of this meteorological phenomenon across a diverse group of animals, which may prove useful in contextualizing future observations. ABSTRACT: The infrequency of a total solar eclipse renders the event novel to those animals that experience its effects and, consequently, may induce anomalous behavioral responses. However, historical information on the responses of animals to eclipses is scant and often conflicting. In this study, we qualitatively document the responses of 17 vertebrate taxa (including mammals, birds, and reptiles) to the 2017 total solar eclipse as it passed over Riverbanks Zoo and Garden in Columbia, South Carolina. In the days leading up to the eclipse, several focal teams, each consisting of researchers, animal keepers, and student/zoo volunteers conducted baseline observations using a combination of continuous ad libitum and scan sampling of each animal during closely matched seasonal conditions. These same focal teams used the same protocol to observe the animals in the hours preceding, during, and immediately following the eclipse. Additionally, for one species—siamangs (Symphalangus syndactylus)—live video/audio capture was also employed throughout observations to capture behavior during vocalizations for subsequent quantitative analysis. Behavioral responses were classified into one or more of four overarching behavioral categories: normal (baseline), evening, apparent anxiety, and novel. Thirteen of seventeen observed taxa exhibited behaviors during the eclipse that differed from all other observation times, with the majority (8) of these animals engaging in behaviors associated with their evening or nighttime routines. The second predominant behavior was apparent anxiety, documented in five genera: baboons (Papio hamadryas), gorillas (Gorilla gorilla gorilla), giraffes (Giraffa cf. camelopardalis), flamingos (Phoenicopterus ruber), and lorikeets (Trichoglossus moluccanus and Trichoglossus haematodus). Novel behaviors characterized by an increase in otherwise nearly sedentary activity were observed only in the reptiles, the Galapagos tortoise (Chelonoidis nigra) and the Komodo dragon (Varanus komodoensis). While the anthropogenic influences on animal behaviors—particularly those relating to anxiety—cannot be discounted, these observations provide novel insight into the observed responses of a diverse vertebrate sample during a unique meteorological stimulus, insights that supplement the rare observations of behavior during this phenomenon for contextualizing future studies.