2017 solar eclipse. Photo by Drew Rae, courtesy of Pexels.

On the 21st of August 2017 the majority of the eastern United States experienced an astronomical phenomenon that only few bear witness to during their lifetimes- a total solar eclipse.  A unique event occurring only approximately every 375 years, a solar eclipse occurs when the orbits of the moon and sun converge, producing a total extinguishing of the sun for the period in which the moon passes between the sun and the earth.  Producing a characteristic halo around a blackened spot, the total solar eclipse has been a phenomenon of much interest to the scientific community, particularly to animal behaviorists.

While animal behavior has been studied during solar eclipses at various times around the world, a new study based at the Riverbanks Zoo in Colombia, South Carolina presents accounts of the behavioral responses of 17 species (including mammals, birds, and reptiles) to the 2017 total solar eclipse which produced near 3 minutes of total darkness (Harstone-Rose et. al 2020).  This study expands upon previous observations, with three primary outcomes.  Animals were documented as falling into one or more of four behavior categories, normal behavior, evening behavior, novel behavior, and apparent anxiety.

Observation during the eclipse produced data which indicated behavioral changes in 76% of the species studied.  Normal or baseline behavior was continued by grizzly bears, seals, sea lions, and the kookaburras, with no noticeable changes in behavior during or after the eclipse.  The majority of species which did exhibit behavioral changes fell into the category of evening behavior, wherein the animals began to behave in ways typical of their nighttime routines.  Gorillas, giraffe, elephants, cockatoos, lapwings, lorikeets, tawny frogmouths and komodo dragons all displayed behavior which could clearly be linked to their evening routines through keeper observation.

One example of nighttime behavior was the lorikeets, who exhibited a large and syncronous response to the eclipse.  Prior to the event, the lorikeets were observed acting independently, vocalizing, moving between perches, and drinking nectar offered by visitors.  During the totality of the eclipse, the flock flew en masse towards the end of their aviary,  to the location of their nest boxes.  The flock then engaged in loud and clamorous vocalizations which are typical of lorikeet populations during the evening prior to rest.  As the eclipse passed, the birds fell quiet and eventually resumed their normal daytime behavior and vocalizations.

Potential anxiety was the second most common response indicated by the keepers who observed their animals during the eclipse.  Baboons, gorillas, komodo dragons, zebras, flamingoes, giraffe, and Galapagos tortoises were documented as displaying signs of anxiety such as pacing or swaying, running, high vigilance, and abnormal huddling.  The last category was novel behaviors, which were documented in both Galapagos tortoises and siamangs.  For example, following the totality of the eclipse, all four tortoises were observed gazing up at the sky for a period of nearly 10 minutes.

The unique behavior of these zoo animals during the 2017 solar eclipse serves as the most detailed and diverse compendium of observation during eclipse to date.  These observations show that nearly 3/4 of the species studied exhibited some behavioral response to the eclipse, suggesting that animal behavior in the wild could be similarly modified on a large scale during this variety of solar event.  Although a wild study of this nature poses significantly more challenges, researchers are hopeful that in the future we will gain further understanding of the role of meteorological phenomena on animal behavior and activity.

 

References

Hartstone-Rose, A., Dickinson, E., Paciulli, L. M., Deutsch, A. R., Tran, L., Jones, G., & Leonard, K. C. (2020). Total Eclipse of the Zoo: Animal Behavior during a Total Solar Eclipse. Animals, 10(4), 587.

hyperlinked: article with video of eclipse at the zoo

https://www.newsobserver.com/news/local/article168420637.html