“While driving on these small winding mountain roads, we kept an eye out for the snakes crossing the road,” Gerke said, noting that the snakes are active when the weather warms up. “Every time we found one, we jumped, grabbed it, and brought it back to the laboratory at Fukushima University.”
As long as a snake was large enough, Gerke and his team would wrap a piece of duct tape around its body. Then they stuck a tiny GPS tracking device and a tiny dosimeter – a radiation measuring tool – onto the tape, which allowed them to remove the devices after the study was completed. Then they brought the snake back to its natural habitat. The team outfitted nine snakes this way, after which they collected the data remotely.
Scientists have identified more than 1,700 sites in the region frequented by snakes. It turns out that Fukushima rat snakes avoid evergreen deciduous forests but spend time near streams, roads, and grasslands. They also frequent trees and buildings.
What is the snakes reveal? Some of the radiation exposure of snakes in the Fukushima Exclusion Zone comes from contaminated prey they eat, but most (80%) comes from contact with contaminated soil, trees and plants.
“Understanding how contaminants move in an ecosystem and how they move in different animals throughout the food web gives us a better idea of the impacts. [of the nuclear disaster] to the ecosystem, ”said Gerke.
The exposure of an individual snake is related not only to the small region in which it spends time, but also to its behavior. For example, snakes that spent time in abandoned buildings had lower doses compared to those that did not, suggesting that buildings may act as shields against contamination. Additionally, snakes that spent more time in trees had lower doses compared to snakes that spent more time on the ground. Gerke hypothesizes that species that spend their time primarily on the ground are potentially more vulnerable to negative health effects from radiation, if negative health effects on snakes exist.
“At the level of the population, we do not think that they are as impacted [by radiation]. But there could be things happening at the cellular level that we don’t know about, ”Gerke said. She noted that scientists understand the levels of radiation that harm animals like mammals, birds and frogs, but not snakes.
This study was the first to describe the home range size, movements and habitat selection of Japanese Ratsnakes. The results suggest that these animals could be effective bioindicators of local environmental contamination in nuclear disaster zones. But many questions remain. For example, will scientists be able to develop models that clarify the link between habitat use, radiation exposure, and radiation accumulation? If so, they could provide insight into the health effects of chronic radiation exposure in animals or humans.
Why take the time understand snakes, anyway? “I’m afraid of snakes,” Gerke often hears, revealing that she is a herpetologist. Others offer unsolicited testimony suggesting that negative human attitudes towards snakes have the potential to harm animals: “I found a snake in my garden and I killed it.” Gerke grew up in Florida with a rat snake; she confides that she cannot relate to such feelings.
“Teaching people to hate snakes is an ecological disaster,” wrote Melissa Amarello, co-founder of Advocates for Snake Preservation, in an article. According to psychologists, the fear of snakes is learned, not innate. Of the 3,000 species of snakes on the planet, only about 200-7% are capable of significantly injuring or killing a human. Meanwhile, snakes feed on rodents that carry disease. And they play an essential role in the food chain of almost all ecosystems.
In addition to humans’ fear and hatred for snakes which can harm them, these animals face additional challenges that threaten their populations around the world, including legal and illegal taking, habitat loss , disease and climate change.