A pioneering study has found that half of tropical mammal species alter their behavior according to lunar phases. This revelation could have significant implications as human activity continues to transform natural habitats.
The full moon has often been mythologized as a catalyst for strange behavior, but new research suggests such lunar influences may have a basis in reality — at least among tropical mammals. A groundbreaking study published in the Proceedings of the Royal Society B reveals that half of the mammal species in tropical forests adjust their behaviors in accordance with the moon’s phases and the accompanying changes in light levels.
The comprehensive study was an international effort, bringing together experts like Michigan State University ecologist Lydia Beaudrot.
“This research has implications for how habitat degradation may impact some tropical animals,” Beaudrot said in a news release.
To probe how tropical mammals respond to natural changes in light, the researchers analyzed a staggering 2.1 million photographs from automated wildlife cameras set up in 17 protected forests across three continents. The data, sourced from the Tropical Ecology & Assessment and Monitoring Network (TEAM), offered a comprehensive view of nocturnal behaviors across 86 mammal species.
“[F]or tropical forest animals that are awake at night, not all nights are the same. In fact, which species are active depends a lot on the moon,” added Beaudrot, an assistant professor in MSU’s Department of Integrative Biology.
A Nighttime Drama Unfolds
The study revealed that while some species actively avoided moonlight, others were more likely to venture out under moonlit conditions.
“These were the species with the most pronounced reactions,” first author Richard Bischof, a professor at the Norwegian University of Life Sciences, said in the news release.
Overall, the findings showed that about 30% of the species tended to avoid the moonlight, as opposed to 20% that showed a preference for it. Nocturnal creatures, particularly rodents, were predominantly among those avoiding moonlight — a behavior that could be closely linked to their roles as prey in the food chain.
“Imagine playing hide-and-seek in a dark room, and then somebody lights a candle,” Bischof added. “The light, even if it is weak, may make it easier for you to find your way around the room. But if you are the one hiding, you suddenly become a lot easier to detect.”
Implications for Conservation
This newfound understanding of tropical mammal behaviors underscores the urgency of studying these animals under natural conditions, especially as human activity increasingly encroaches on their habitats. Deforestation, habitat fragmentation and artificial lighting can significantly alter the natural lightscape and, consequently, the nocturnal behaviors crucial for survival.
As forest canopies are thinned or replaced altogether, both the natural and artificial light levels can disrupt the delicate balance these species rely on. This can lead to dire consequences for ecological communities, as animals are forced to adapt or face potential declines.
The results of this study could be instrumental in shaping future conservation efforts, offering a clearer picture of how animals interact with their environment under varying lunar conditions. As researchers continue to explore these complex dynamics, their findings may help guide strategies to mitigate the impacts of human-driven habitat changes on tropical wildlife.