This story originally appeared on WIRED en Español, and has been translated from Spanish.
The shadow of a total solar eclipse will cross some regions of Mexico, the United States, and Canada on April 8. The day will be obscured by a brief false night. The infrequency with which such a phenomenon occurs in that area makes it an anomalous event for the animals that live there. So far, most of the information on animal reactions to an eclipse is anecdotal, but there are scientific efforts to make systematic observations. NASA has a plan to increase our scientific understanding of how animals react to eclipses—and to make that happen, it needs your help.
In a total solar eclipse, the moon is positioned in alignment between the Earth and the sun. To view an eclipse, you need to be on the sunny side of the planet (where it's daytime) and be located directly in the path of the lunar shadow as it occurs. The alignment causes the moon's shadow to be cast on the planet's surface. That such an event occurs in the same place only once every 300 to 400 years does not imply, however, that the phenomenon is rare in general. A total solar eclipse occurs, on average, every 18 months somewhere. Many times it falls over the ocean; its audience is usually marine species.
Animal Effects
We know that sunlight is a reliable environmental signal by which plants and animals regulate their biological clock, but how an eclipse affects this process isn't well documented. Scientific reports on changes in animal behavior during eclipses are few and sometimes contradictory.
In the summer of 1991, a group of scientists were in Arizona collecting cicadas for a study. During a partial solar eclipse, they noticed that the cicadas stopped singing when the moon's shadow reduced the sunlight by half. The change in temperature was noticeable; they were in a desert, and they concluded that this influenced the insects.
During a total solar eclipse in Veracruz, Mexico, a team of biologists studied the behavior of colonial orb-weaving spiders. When the umbra (the darkest part of the moon's shadow) arrived, the specimens behaved atypically and began to tear down their webs. When the sun reappeared, most of those that had begun to tear down their webs rebuilt them. During the experiment, the researchers artificially illuminated part of a colony. The spiders that missed the eclipse because of the scientists' light did not exhibit this behavior.
There are more accounts. In Bharatpur, India, under short twilight in 1995, scientists reported night herons leaving their daytime roosts. A year earlier, in Kansas, four species of diurnal birds acted as if it were night. In 1984, captive chimpanzees in Georgia were seen climbing to the highest parts of their enclosure facing the sky.
In other anecdotes, onlookers have reported birds that stop singing, crickets that stopped chirping, or bees that return to their hive, reduce their foraging, or suspend their flight during total darkness. But there are also studies that deny that some of these behaviors occur or can be attributed to the eclipse.
Therefore, NASA scientists plan not only to systematize observations but also to document what people hear and see under the shadow of the moon.
“The Great North American Eclipse”
NASA has created the Eclipse Soundscapes citizen science project to collect the experiences of volunteers. It was inspired by a study conducted nearly 100 years ago by William M. Wheeler and a team of collaborators. At that time, the Boston Natural History Society invited citizens, park rangers, and naturalists to report on the activities of birds, mammals, insects, reptiles, and fish during the summer eclipse of 1932. They collected nearly 500 reports. In their final report they note that some animals exhibited nocturnal behaviors such as returning to their nests and hives or making nighttime vocalizations.
The current NASA study will add observations made during the annular solar eclipse of October 14, 2023 and the total solar eclipse of April 8. The latter will be visible first in Mexico in Mazatlan, then in Nazas, Torreon, Monclova, and Piedras Negras. These localities will be located directly in the umbra of the eclipse and, therefore, their inhabitants will perceive it as total. In nearby regions it will be experienced as a partial eclipse, with less darkness. It will then enter the United States through Texas, passing through Oklahoma, Arkansas, Missouri, Illinois, Kentucky, Kentucky, Indiana, Ohio, Pennsylvania, New York, Vermont, New Hampshire and Maine. Finally, it will travel across Canada from southern Ontario and continue through Quebec, New Brunswick, Prince Edward Island and Cape Breton. Astronomical estimates point to the Mexican port of Mazatlan as the best place to observe the 2024 event, which will experience totality at about 11:07 am local time.
How You Can Help
In the United States, 30 million people live in the area where the eclipse will be perceived as total. If you add in the Mexican and Canadian public, the potential for collecting experiences is immense. That's what NASA wants to take advantage of.
The project foresees several levels of volunteering: apprentice, observer, data collector, data analyst, and facilitator.
The apprentice level is achieved by taking an online course that offers a certificate. Observers must record their experiences with any means at their disposal on the day of the eclipse to share with the project, entering the information in a special format. The role of data collector is for those who register to be fitted with AudioMoth recording devices to capture soundscapes over extended periods. Data analysts will study the recordings obtained by the collectors. Finally, facilitators will be trained to organize groups and brigades to perform some or all of the above activities.
The design of the section of the study that will be fed with the data obtained by the collectors is supported by an advisory board that includes acoustic biologists and soundscape ecologists who will seek to answer two things. The first is whether through ecosystem sounds it is possible to deduce how animal behavior is significantly affected by eclipses. The second is to distinguish the necessary percentage of the phenomenon to produce detectable changes in soundscapes.
This is not the first time that changes in the soundscape have been sought to analyze ecosystem effects during solar eclipses. Nor is it the first time that a zoo has become a study site during such a phenomenon. In 2017, the behavior of 17 species was recorded at Riverbanks Zoo in South Carolina to compare with previous observations of the site. Seventy-five percent of the species observed exhibited some behavioral response to the eclipse, and most exhibited their evening or nocturnal behaviors. The second-most observed behavior was apparent anxiety, which, the study notes, is not known to be in response to the presence of humans.
Solar eclipses have captivated or frightened humankind for millennia. Today, they represent opportunities to broaden our scientific knowledge. Eclipses make it possible to direct measuring instruments into the solar corona. Other projects have evaluated how they affect atmospheric conditions. Nicolaus Copernicus observed this phenomenon through a camera obscura, which, along with other observations, helped explain that the sun, not the Earth, was at the center of our planetary system.
