Some perplexing animal mysteries stumped scientists during the 2017 eclipse. Here’s why

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During the Great American Eclipse of 2017, zoo animals acting strangely took researchers by surprise — the giraffes gathered and broke into a gallop, the Galápagos tortoises began to mate, and the gorillas started to get ready for bed.

These odd behaviors were just a few of several anomalies that scientists stationed at the Riverbanks Zoo and Garden in Columbia, South Carolina, observed during the historic solar event spanning the United States, according to a March 2020 report.

“Giraffes are kind of delicate, they don’t run a lot. When they run, it’s because they’re running from a predator or something like that,” said lead study author Dr. Adam Hartstone-Rose, professor of biological sciences at North Carolina State University in Raleigh.

“It was kind of amazing and mind-blowing,” he said. Animal keepers at the Nashville Zoo at Grassmere also documented giraffes galloping during the brief moments in 2017 when the sky darkened in the middle of the day.

With the upcoming solar eclipse on April 8, the researchers plan to build upon their past study at a different zoo located within the path of totality. That’s the swath of Mexico, the US and Canada that the moon’s shadow will cross, obscuring the sun for three or four minutes at a time at geographical points along the way.

And you can help scientists unlock the mysteries of these unusual behaviors. While many people prepare to look to the sky for the dazzling event, others may want to take a few moments to watch the critters in their own backyard, said Hartstone-Rose, who is one of the principal investigators of Solar Eclipse Safari, a citizen project aiming to collect observations from people viewing the eclipse across the entire path.

Get involved in unraveling animal secrets

Hartstone-Rose plans to bring a team of graduate student researchers to the Fort Worth Zoo in Texas, which will experience the solar eclipse on April 8 from about 12:22 p.m. to 3:01 p.m. CT, with the moment of totality occurring for nearly 2 ½ minutes at 1:40 p.m. CT, according to NASA. The researchers will study certain animals to determine whether they repeat the same odd behaviors. But members of the public also can help with their own research.

And regular folks won’t just be watching at a zoo. The citizen project calls for observations from all sorts of environments, including cities with pigeons and squirrels, mountain ecosystems with woodland critters, farms with livestock, and more.

“There could be all sorts of things. We’re hoping that we even get kids watching their dogs in their backyard and seeing if their dogs behave interestingly during the eclipse,” Hartstone-Rose said.

The path of totality spans across more than a dozen US states, but even someone who is not directly on the path will most likely experience some percentage of the sun being covered by the moon. Hartstone-Rose is interested in reports from across North America to determine whether some animals only respond at a certain percentage of the sun’s coverage, he said.

“It’s a project that anybody anywhere on the path of totality, or even not in the path of totality, could do using our protocols and contribute data to our study, and help us understand more broadly how animals behave during the eclipse,” he added.

But that’s not the only way citizen scientists can get involved. You could also join NASA’s Eclipse Soundscapes Project. The space agency will collect observations from the public on animal behaviors as well as human reactions to the eclipse through written multisensory reports — such as what the observer saw, heard or felt — and audio recordings of the environment during the solar event.

Total solar eclipses are infrequent events that provide scientists with rare opportunities to collect data on behavioral responses to the phenomenon, said Kelsey Perrett, communications coordinator for the Eclipse Soundscapes Project. The next total solar eclipse that will be visible across the contiguous United States won’t appear until August 2044.

Why do animals react to the eclipse?

Reports of animals acting strangely during a solar eclipse date back hundreds of years, according to NASA, but the causes and effects of the unusual behaviors are not fully understood.

The researchers studied 17 species during the 2017 event and found behavioral responses to the eclipse in approximately 75% of the zoo animals observed, with the majority either displaying evening activities or behaviors that signal anxiety.

Hartstone-Rose believes there are two possible reasons for the animals’ responses to the eclipse. First, the animals were reacting to the natural light dimming and the temperature dropping as the sun disappeared behind the moon. Second, the animals were reacting to the crowd of zoo goers’ excitement and commotion while the eclipse was happening.

The moon’s interference with daylight caused by a total solar eclipse likely affects animals because of what is known as circadian rhythm, the internal biological 24-hour clock that tells a person or an animal how to respond to the amount of light they are receiving, said Dr. Bryan Pijanowski, professor of forestry and natural resources and the director for the Center for Global Soundscapes at Purdue University in West Lafayette, Indiana. He was not involved in the March 2020 study.

“Most animals respond to (the light dimming from the eclipse) in a way where it’s like, ‘OK, it’s time to either sit down and rest and go to sleep.’ … And then there are the nocturnal animals that suddenly say, ‘oh, it’s time for me to wake up and be active,’” he added.

A better understanding of how animals respond to the eclipse could inspire further research on how animals, particularly insects, are affected by light pollution, said Pijanowski, who is also part of the science advisory board for the Soundscapes Project.

How have animals reacted during past eclipse events?

The most consolidated study is from nearly 100 years ago, when a team of scientists led by entomologist William M. Wheeler collected almost 500 observations from the public. For example, people told the researchers that during the August 1932 eclipse’s totality they noticed crickets chirping as if it were nighttime and bees attempting to return to their hives. The study, published in March 1935, also included observations of mammals, birds and cold-blooded vertebrates.

Researchers have made additional observations of specific animals’ reactions over the years during solar eclipse events, including studies of captive baboons that increased grooming behaviors, brown pelicans that began to roost, colonial orb-weaver spiders that took down their webs and certain amphibians that became more vocal.

Hartstone-Rose plans to have researchers stationed near the giraffe enclosure in April to see whether the galloping behavior occurs again and is hoping people stationed at other zoos will do the same.

A few of the other animals the research team will be scrutinizing include reptiles — particularly tortoises, to see whether the typically slow-moving giants will become more active — as well as primates, such as bonobos, which tend to have sex when under stress, Hartstone-Rose said.

Watching the eclipse at a zoo

The researchers will have to be aware of the limitations of crowd participation impacting the findings when it comes to observing animal behavior at the Fort Worth Zoo this year, Hartstone-Rose said. But he hopes there will be plenty of other observations from people who are not near crowds.

“It’s the nature of the beast. Eclipses are super exciting. We don’t want to do anything that diminishes people’s excitement during the eclipse,” he said.

The zookeepers also will contribute to data by observing animals within their area of expertise, said John Griffioen, assistant director of animal programs and conservation at Fort Worth Zoo.

The highly vocal animals of the zoo that communicate with one another often, such as the elephants, flamingos and parrots, will be of particular interest, Griffioen said, to determine whether the totality causes the animals to become quieter or louder.

In addition to the Fort Worth Zoo, several zoos across the path of totality have announced events open to the public for eclipse viewing, including the Buffalo Zoo in New York, the Little Rock Zoo in Arkansas, the Toledo Zoo in Ohio and the Indianapolis Zoo.

How you can help NASA with research

The Eclipse Soundscapes Project began last October with the annular eclipse, also known as the “ring of fire.” More than 800 people participated in the project, Perrett said. The space agency is expecting far larger numbers for the 2024 total solar eclipse — nearly 2,500 people have already signed up, she added.

Wheeler’s 1935 citizen study inspired the project, according to the website. The space agency’s researchers are particularly interested in studying crickets and other vocal nocturnal insects to find out whether they will begin chirping as the moon shrouds the sun, Perrett said.

The NASA project is open to all volunteer participants, including those who are blind or have low vision, according to the news release. What’s more, it’s not necessary to have an animal within eyesight to take good observations, as listening is also an important sense to use during the eclipse, Pijanowski said.

“If we get even a handful of people who go out and experience the eclipse in a new way, we’ll consider it a success,” Perrett said in an email. “When it comes to data, it’s the more the merrier. The more people who participate, the better we can answer our questions about how solar eclipses impact life on Earth.”

The Solar Eclipse Safari and Eclipse Soundscapes Project will capture the public’s observations through forms found on their respective websites. But if you are just looking to take in the “once in a lifetime” solar event for yourself, that’s fine, too, Hartstone-Rose said.

“(During a total solar eclipse) you have so many different ways the light is scattering, so there’s these beautiful colors of orange and purple and green. … The wind speed drops and becomes very, very calm. And so everything happens within a very short time period, all at the same time,” Pijanowski said. “It’s kind of a great human sensory experience to be in the middle of a total solar eclipse.”