Nestled in the heart of the California redwood forest is a roving colony of hoary bats, scientifically known as Lasiurus cinereus. A hoary bat has the ability to travel hundreds of miles. It flies throughout western North America before resting to California’s North Coast.
It is uncommon for some species of bats to migrate or hibernate. However, it’s rarer to find species to do both. The Hoary Bat, North America’s largest bat at 5 inches length, is covered with unique fur from which it takes its name.
Researchers together with the U.S. Forest Service’s Pacific Southwest Research Station have recorded the first evidence of hoary bats migrating to the state of torpor, or hibernation. The coverage has been published earlier this month in Scientific Reports just in time for National Bat Week, Oct. 24-31, “First Direct Evidence of Long-distance Seasonal Movements and Hibernation in a Migratory Bat” reports newly discovered behaviors in hoary bats.
“It’s commonly assumed that species that migrate do so to reach areas that allow them to continue feeding and remain somewhat active throughout the winter,” said lead author
Ted Weller, an ecologist with the Forest Service said, “but our findings surprised even our own research team by showing that hoary bats spend much of the winter in hibernation.”
Back in September 2014 at Humboldt Redwoods State Park, Weller and his team equipped several bats with GPS tracking devices and another group of bats with a device to monitor the light levels, body temperature and their activity, in order to study how bats respond to different weather conditions.
Weller said, “While such tracking and monitoring technology has existed for a while, it hasn’t been until somewhat recently that these units were made small enough to be affixed to animals of this size,”
After several months, they were able to capture a third bat, and produced the most intriguing behavior. The third bat flew more than 600 miles. It made a loop into southern Oregon, then into California. It then flew over the Nevada border, and then back again into California.
In a statement, Weller said, “It’s hard to determine what led to such a journey,”
“Was he seeking favorable temperatures and humidity for roosting and foraging? Was he trying to intercept females to mate with as they migrated to their wintering grounds?” He added.
Meanwhile, the GPS tracking devices equipped to the other group of bats also gained new insights into the species. Two bats from that group were recovered in spring, with one of the bat’s devices generated 224 days of data. In the span of November 2014 through April 2015, the bat showed signs of being in a state of torpor. This was based on low body temperature and inactivity.
This study leads researchers to the question: Why would a species capable of migrating, hibernate? The answer could lie within the bats’ roosting habitat.
“Hoary bats roost outside in trees as opposed to inside caves,” Weller said. “It’s possible that hoary bats are evolved to hibernate. Hosever, they would freeze if they did so in their northern summer territories.”
The Redwoods is an ideal habitat for the bats because it offers an environment with lots of shelter. Moreover, It has cool temperatures and plenty of moisture to reduce the risk of dehydration.
Research provided a glimpse into Hoary Bat Habits
Similar to other migratory species, understanding seasonal movements and wintering habits are essential for conservation efforts. And because most bat research is confined to summer when bats are most active, these findings are especially useful.
“This research has provided us with a valuable look into the lives of hoary bats rarely before seen, and until now, never before documented to this extent,” Weller said.
“Knowing more about their lives outside of the summer months will help us better understand what steps might best promote their conservation.”
The post First Direct Evidence of Hoary Bats Migration And Hibernation appeared first on Newsline.
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