What do animals do during a solar eclipse?
If the sun winks out in the middle of the day, birds may fall silent and bees leave the fields. Tales have reported animals behaving strangely during a solar eclipse's totality. That’s when the moon completely blocks out the sun. And it’s something that will happen today along a path spanning the entire United States.
There’s a lot of anecdotal evidence for how animals and even plants respond to a totality, says Elise Ricard. “But [there’s] not a lot of hard science,” she adds. Ricard is the spokesperson for an eclipse project called Life Responds. The California Academy of Sciences in San Francisco is running it. She notes that tales alone aren’t enough for scientists to conclude anything certain about how wildlife typically behave during a solar eclipse.
But such tales do go way back. Perhaps the earliest record comes from 1544. That’s when an unknown observer wrote that “birds ceased singing” during a total eclipse. Another observer in 1560 reported “birds fell to the ground.”
In the past century or so, however, scientists have tried to approach the question in a more systematic way. The Boston Society of Natural History in Massachusetts collected observations during a 1932 eclipse. (It crossed parts of Maine, New Hampshire and Vermont.) Study volunteers took part in what they believed was “the first comprehensive and scientifically conducted study of the behavior of animal life during a total eclipse.”
Crickets chirped, people reported. Frogs croaked. Gnats and mosquitoes swarmed. (“Our stockings attested to the bites, for they drew blood and never let up,” one volunteer noted.) Bees returned to hives. Chickens came home to roost.
Eclipse studies in the 1960’s and 1970’s reported small light-sensitive crustaceans (Krus-TAY-shuns) and zooplankton (ZO-plank-tun) swimming towards the surface. That is similar to what the tiny animals do at night. The sun’s brief absence during a 1991 eclipse prompted orb weaver spiders to take down their webs. And during an annular eclipse in 1984, captive chimpanzees scaled a climbing structure. Then they turned their faces to the blocked sun. (An annular eclipse is when the moon blocks all but a ring of bright light.)
As interesting as these tales are, they also are quite limited. That could change with the 2017 eclipse. Many people now have smartphones. This means that crowdsourced research can yield more and better-coordinated observations than ever before.
This year, the California Academy of Sciences in San Francisco solicited citizen scientists to collect data. Observers will use the academy’s iNaturalist app. A team there hopes to get more data from a larger area than during any previous eclipse.
“We’re looking for observations from anywhere in the continental United States,” Ricard says. They hope to get participants directly in the path of the totality. But even someone who sees only a partial eclipse may also take part. Indeed, Ricard wonders whether partial eclipses will have a similar effect on wildlife. “I’d be interested to know,” she says, “where the line is, what percentage of totality you see responses for.”
anecdotal (n. anecdote) An adjective to describe such things as data, events or processes that are based on limited (and usually nonscientific) observations. For instance, they may be based on what only one person observed or experienced. Or it could be based on random observations, not a systematic one, designed to scientifically test an idea.
annular eclipse An unusual form of solar eclipse where the moon appears smaller than the sun. So when it passes directly in front of the sun, a ring of light surrounds the moon on all sides. This ring of light is called an annulus, making the event an annular eclipse.
app Short for application, or a computer program designed for a specific task.
behavior The way something, often a person or other organism, acts towards others, or conducts itself.
birds Warm-blooded animals with wings that first showed up during the time of the dinosaurs. Birds are jacketed in feathers and produce young from the eggs they deposit in some sort of nest. Most birds fly, but throughout history there have been the occasional species that don’t.
citizen science Scientific research in which the public — people of all ages and abilities — participate. The data that these citizen “scientists” collect helps to advance research. Letting the public participate means that scientists can get data from many more people and places than would be available if they were working alone.
crowdsourcing (v. to crowdsource) A term coined in 2005 for the collection of data from a large community of volunteers — often over the Internet. For instance, those volunteers may collect information intentionally (such as data on cloud cover, the appearance of a particular butterfly or a recording of the call of a certain bird), then send the data to some researcher. Alternatively, an app downloaded on someone’s phone might collect light, vibrations or some other information periodically — and automatically — and then relay it over the Internet to researchers.
crustaceans Hard-shelled water-dwelling animals including lobsters, crabs and shrimp.
eclipse This occurs when two celestial bodies line up in space so that one totally or partially obscures the other. In a solar eclipse, the sun, moon and Earth line up in that order. The moon casts its shadow on the Earth. From Earth, it looks like the moon is blocking out the sun. In a lunar eclipse, the three bodies line up in a different order — sun, Earth, moon — and the Earth casts its shadow on the moon, turning the moon a deep red.
roost A place where winged animals temporarily rest or sleep. The term also refers to the act of resting on a branch or above-ground perch.
smartphone A cell (or mobile) phone that can perform a host of functions, including search for information on the internet.
solar eclipse An event in which the moon passes between the Earth and sun and obscures the sun, at least partially. In a total solar eclipse, the moon appears to cover the entire sun, revealing on the outer layer, the corona. If you were to view an eclipse from space, you would see the moon’s shadow traveling in a line across the surface of the Earth.
totality (in astronomy) The brief period during an eclipse when one object totally obscures another. For a solar eclipse (when viewed from Earth), this would be when the moon appears to completely block out the sun’s light.
zooplankton Small organisms that drift in the sea. Zooplankton are tiny animals that eat other plankton. They also serve as an important food source for other marine creatures.
Journal: W. M. Wheeler et al. Observations on the behavior of animals during the total solar eclipse of August 31, 1932. Proceedings of the American Academy of Arts and Sciences. Vol. 70, March, 1935, p. 33. doi: 10.2307/20023118.
Journal: E. Kampa. Observations of a sonic-scattering layer during the total solar eclipse, 30 June, 1973. Deep-Sea Research. Vol. 22, 1975, p. 417.
Journal: G. Uetz et al. Behavior of colonial orb-weaving spiders during a solar eclipse. Ethology. Vol. 96, January 12, 1994, p. 24. doi: 10.1111/j.1439-0310.1994.tb00878.x.
Journal: J. Branch and D. Gust. Effect of solar eclipse on the behavior of a captive group of chimpanzees (Pan troglodytes). American Journal of Primatology. Vol. 11, 1986, p. 367. doi: 10.1002/ajp.1350110407.