Study: Snakes' unique climbing tactic contributes to outages, birds' demise

PREDATOR: A file photo of the predatory brown tree snake on Guam is shown. Courtesy USDA/Wildlife Service

The pesky brown tree snakes have something in common with cowboys and coconut climbers, to the detriment of Guam's wildlife and residents who hate power outages.

A study released Tuesday found that the brown tree snake is capable of scaling cylindrical, vertical surfaces by forming itself into a lasso – similar to the type of rope loop cowboys use – for the reptile to form itself into a loop to get a good grip and climb, inch by inch, up a vertical slippery pole.

A recorded video of the brown tree snake's climbing strategy on Guam also bears resemblance to what traditional coconut climbers do as they hug a coconut tree trunk using their arms and legs to get a good grip, and then pull themselves upward, little by little.

Biologists Julie A. Savidge, Thomas F. Seibert and Martin Kastner conducted the study, which was published in full Tuesday in Current Biology magazine. The Smithsonian Magazine also reported on the findings of the study, in a report titled "Invasive Brown Tree Snakes Stun Scientists With Amazing New Climbing Tactic."

The biologists called the new brown tree snake move "lasso locomotion." The biologists did not make a comparison with traditional coconut climbers.

"We document a new mode of snake locomotion – ‘lasso locomotion’ – that allows the brown tree snake (Boiga irregularis) to ascend much larger smooth cylinders than any previously known behavior," the study states, as reported in Current Biology. "This lasso locomotion may facilitate exploiting resources that might otherwise be unobtainable and contribute to the success and impact of this highly invasive species.

So why should Guam care about the brown tree snakes' newly documented moves?

It serves as a wake-up call that an experiment to try to protect bird nests on the island from the predatory snakes by using poles to prop up the nests, high from the ground, may not be that effective.

In a time-lapse video recording, presented as part of the study, a brown tree snake was recorded on Guam, in 2017, making its way up a shiny pole and reaching a bird's nest. Three locally endangered Micronesian starlings were killed in the recorded act of "lasso locomotion" invasion, according to the study.

There's another reason why the study impacts Guam residents.

Those outages that the Guam Power Authority has attributed to brown tree snakes, it turns out, may have been executed by the snakes that have the capability to lasso their way to the top of power poles.

"Collectively, these abilities contribute to their detrimental ecological and economic impacts, such as decimating the native vertebrate fauna of Guam and short-circuiting electrical lines," the study states.


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