Observations from around the world have revealed that animals change their behavior during total solar eclipses. Until now, the reports were few and far between, and conclusions could not be drawn from them. This is about to change as a new app operating during the total solar eclipse in the U.S. aims to collect data from many locations in order to create a larger knowledge base

Humans were always fascinated with celestial objects, especially with the extraordinary events during which the sun disappears in the middle of the day and darkness rules the land, if only for a few minutes. Some scientists have now decided to direct their gaze at what is happening on the ground during this time – instead of looking up to the skies.

Dr. Douglas Duncan, an astronomer from the University of Colorado, has observed ten total solar eclipses and also did not miss the most recent one (August 21, 2017) in the U.S. He is one of those who were not focusing only on the sky, and therefore has witnessed some strange animal behaviors. Duncan said in an interview that during a total solar eclipse in Bolivia in 1994, he and his colleagues soon found themselves surrounded by llamas, which, by the end of the event, had left the area in an organized single file. In 1998, he stayed on a boat near the Galapagos Islands; a few minutes before the eclipse began, dozens of whales and dolphins arrived at the area, swimming back and forth next to the boat. After the event, they were nowhere to be found.

Scientists know that numerous plants and animals depend on the light cycles of the sun and moon and adapt to them. Animal behavior during a solar eclipse is a particularly fascinating phenomenon, since there is no doubt that such a dramatic event, of lighting and temperature changes, confuses the animals and unsettles them. The evidence collected so far on the effect the eclipse has on animal behavior in nature is interesting but not sufficient to be conclusive.

Night in the middle of the day

A total solar eclipse occurs when the sun, moon, and Earth are aligned on the same axis, so that the moon completely blocks the sun. Night in the middle of the day is not a normal occurrence, and accordingly, a solar eclipse only happens once every 18 months, each time at a different location on Earth. A total solar eclipse happens at any given point on Earth about once every 370 years.

Over the years, scientists have attempted to document animal behavior during solar eclipses. In a study from 1984, a group of chimpanzees residing at the Primate Research Center in Georgia, USA, was documented. Researchers reported that during the eclipse, the chimps huddled on a climbing structure and looked into the sky.

And what happens in the great outdoors? Researchers that observed dairy cattle during the 1999 eclipse in Europe did not detect behavioral changes. But researchers from Mexico reported that during the 1991 solar eclipse, they observed spiders that were breaking down their own webs, while spiders that were kept under artificial light did not do so. A study of fish behavior during the 1998 solar eclipse in the Galapagos Islands reported that diurnal fish (i.e., fish active during daytime) stopped their feeding activity and hid inside caves and corals.

Some researchers think that birds may be affected by solar eclipses more than other animals since they are accustomed to return to their hideaways at sunset. Researchers observing bird behavior during the Venezuela solar eclipse in 1998 reported that at its peak, birds flew to their hideaways, returning to their usual business once it ended, as if nothing had ever occurred. The locals, who are familiar with the birds' usual behavior, told the researchers that during the eclipse, the birds acted as if the sun was setting and the day has come to an end.

צל הירח על כדור הארץ. Credit: NASA
The shadow of the moon on Earth. Credit: NASA

Technology at the service of science

These types of studies are very problematic, since total eclipses occur each time at a different location on Earth and they are too far apart in time from each other to enable the collection of sufficient data. A good experiment is one that allows the investigator to control the varying parameters of the experiment and repeat the tests many times in order to assess the credibility of the results. All of these factors make studying animal behavior during a total solar eclipse very difficult.

However, science does not give up easily, and wherever difficulty lies, creativity emerges. Researchers from the California Academy of Sciences recruited the wisdom of the masses for documenting animal behavior during the recent solar eclipse in the U.S. They developed an app enabling anyone to document wildlife during the eclipse, which hopefully enabled them to collect enough observations for their research. Only by accumulating a large amount of data, which was not previously possible, will they be able to detect behavioral patterns and draw conclusions.

Beyond the information that studies such as these will provide on the effects of this natural phenomenon on animals, they may also afford us a glimpse of predicted animal responses to expected climate and environmental changes. The next solar eclipse in Israel will take place in 2020, and the next full eclipse in Europe and Africa will only be in 2028. So just in case, let's put a reminder in our calendars to take note of the wildlife around us during those times – and look not only up into skies, but also gain something important from them.

Translated by Elee Shimshoni.