What happens to animals during a solar eclipse?

September 28, 2017
5 min
Observations made during total solar eclipses around the world revealed that animals change their behavior, but until now there were only a few reports that are hard to draw conclusions from. A new app that was operated during the total solar eclipse in the United States aims to collect data from many locations in order to create a larger knowledge base

The human race has been always fascinated with anything that has to do 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. However, some scientists have decided to take a look at what is happening on the ground during this time, instead of looking up to the skies.

Dr. Douglas Duncan, astronomer from University of Colorado, has observed ten total solar eclipses and also did not miss the most recent one that took place in the US on August 21st. He is one of those who were not only focusing on the sky, and therefore has witness some strange animal behaviors. Duncan said in an interview that during the total solar eclipse in Bolivia in 1994, he and his colleagues soon found themselves surrounded by llamas, which by the end of the event, stood in an organized single file and left the area. In 1998, he stayed on a boat near the Galapagos Islands, and 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 many plants and animals depend on the light cycles of the sun and moon and adapt according to them. Animal behavior during a solar eclipse is a particularly fascinating phenomenon, since there is no doubt that such a dramatic event, of changes in lighting and temperature, confuses the animals and unsettles them.  The evidence collected so far is interesting but not sufficient for drawing conclusions on the effect the eclipse has on animal behavior in nature.

Night in the middle of the day

A total solar eclipse occurs when the sun, the 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, in a different location on Earth each time. Each point on Earth will have a total solar eclipse 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 eclipse that took place in Europe in 1999 did not observe any behavioral change. In contrast, researchers from Mexico reported that during the 1991 solar eclipse they observed spiders that were breaking down their own webs, while spiders kept under artificial light did not. A study observing fish behavior during the 1998 solar eclipse in the Galapagos Islands reported that diurnal fish (i.e., fish that are active during daytime) stopped their feeding activity and hid inside caves and corals.

Certain researchers think that birds may be affected by solar eclipses more than other animals since they are used to return to their hiding places at sunset. Researchers that observed bird behavior during the Venezuela solar eclipse in 1998 reported that at its peak the birds flew to their hiding places. By the time it was over, they returned to the bay and went about their business like nothing ever happened. 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.


The shadow of the moon on Earth. Credit: NASA

Technology at the service of science

These sorts of studies are very problematic, since a total eclipse occurs every time at a different location on Earth and too far apart in time from each other in order to collect enough data. A good experiment is such that allows the scientist 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, you can find creativity. Researchers from the California Academy of Sciences recruited the wisdom of the masses for documenting animal behavior during the recent solar eclipse in the US. They have developed an app that enables any person 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 effect of this natural phenomenon on animals, we may also get a glimpse of their predicted reactions to the climate and environmental changes that are expected to take place on Earth. 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. Therefore, just in case, let's put a reminder in our calendars to notice wildlife around us during those times, so that we not only look up into skies, but also gain something important from them.

Translated by Elee Shimshoni.