In total solar eclipses, many creatures react as if it were nighttime, UF researcher says

When the orbiting moon passes between the sun and Earth on April 8, skies will darken. Birds will stop singing. Frogs will stop croaking. And crickets will stop chirping.

Animals respond to total solar eclipses and it leaves scientists marveling at rare, sudden behavioral changes while also questioning what it is that makes creatures do what they do during the day and night.

Marc Branham, a professor of entomology at the University of Florida Institute of Food and Agricultural Sciences, experienced this during a total solar eclipse in 2017. As the skies darkened, Branham witnessed birds and grasshoppers go silent even though it was afternoon.

"I study fireflies and I was curious as to whether there might be a firefly flashing in this really brief period of darker daylight," he said in an interview. "I saw fireflies start to flash, and it was the first time I had ever seen that."

When he returned home, Branham said he researched what had occurred.

He learned that, for instance, honeybees will react to the eclipse as if it were nighttime.

"They will stop leaving their hives for foraging flights and stay at the hives like it's time to retire for the evening," Branham said.

"It's so surprising how this happens. It's like a lot of these organisms have known behavioral patterns. They seem to know what time it is over the course of the 24-hour period based on on their own internal clock, which is called the circadian rhythm," he said. "But they also get a lot of environmental cues, based on how much light there is."

Branham said there isn't much research into animal behavior during eclipses, in part because they are rare.

"I feel like most people including biologists are all looking up at the actual eclipse," he said, "and they're not looking around them in their surrounding environment."

Another professor who has been drawn to eclipses and the planet's reactions to them is Doug Duncan, an emeritus faculty member of astrophysical and planetary sciences at the University of Colorado.

Duncan has chased eclipses since 1970 and now leads eclipse trips around the world.

On his website, he posted a video describing some of the animal reactions he’s seen. Once, in Bolivia, he and people around him were all marveling at the eclipse when someone told the group to look down. When Duncan did, he said he was surrounded by llamas.

“I don’t know where they came from. And when the eclipse was over, they all lined up in a line and they marched away," he said.

“At another total eclipse in the Galapagos," Duncan said, "we were on a small boat and five minutes before totality, every whale and dolphin in the vicinity, dozens, surfaced and swam back and forth and watched the eclipse with us.”

While the phenomena adds to the overall weirdness of a total eclipse, alas, Florida will not experience it in full splendor on Monday. That's because the eclipse's path of totality ― a slightly over 100-mile-wide line stretching from Eagle Pass, Texas, to Houlton, Maine, the northern terminus of Interstate 95 ― will only be partial across the Sunshine State. Viewers in Daytona Beach will have about 63% coverage, according to Terry Oswalt, a professor of physical sciences at Embry-Riddle Aeronautical University.

Branham said areas with 90% totality or less won't see much change. Partial eclipses offer a lesser darkening, that of a cloudy day, as opposed to sensation of nightfall descending.

Those who travel to the path of totality, or who stick around long enough for the next total solar eclipse in Florida ― in 2045 ― will experience something almost poetic.

"We spend so many years and so many days per each year on this schedule. It gets light int the morning. The sun goes up, it gets brighter and brighter and brighter as the sun gets higher. In the evening, it sets and it gets dark."

All creatures become accostomed to the usual, the normal.

"And then when we have a very rare event like this, where it's so different ... and it just feels surreal to us," Branham said. "But the organisms around us act differently.

"It makes me think about how do we know when it's evening. How do we know when it's dark? What actually is evening? What are those cues to trigger an organism to be nighttime active, or to be daytime active?"

It leaves Branham wondering if studying the behavior of creatures during a solar eclipse can help humans learn more about their day-in, day-out experiences.

Note: This story has been corrected to reflect the fact that the next total solar eclipse in Florida will be in 2045.

Solar Eclipse 2024: How long will the solar eclipse darkness last in your city? Explore these interactive maps.

This article originally appeared on The Daytona Beach News-Journal: University of Florida prof wonders why animals react to solar eclipses