[애니멀피플]
Roll it up with your body to make a noose, then wriggly move up
A brown tree snake climbing a smooth metal cylinder. After winding the body around to form a noose, it climbs with the friction and the writhing of the body. Provided by Julie Savage et al. (2021)’Current Biology’
Snakes move sideways as if swimming on the desert sand, and also jump from tree to tree. A new method of movement of snakes that has not been known has been discovered. It is a’noose movement’ in which the body is rotated to create a noose and then climbs a smooth vertical cylinder using the friction force. The protagonist of the new migration method is the brown tree snake, a notorious alien species that invades Guam, killing most of the native birds and causing great damage to residents.
After the brown tree snake entered Guam, 10 native bird species were put into extinction. In the process of establishing conservation measures for the other two species, a different way of moving this snake was discovered. Courtesy of Björn Lardner, US Geological Survey.
This snake, which lived in Australia and Papua New Guinea, is known to have entered Guam by US military cargo planes in the late 1940s and early 1950s. This snake, which increased rapidly in the 1960s, drove 10 species of native birds that only lived in Guam to extinction, and became a big social problem as it penetrated the house with a body weighing 2.3m and weighing 2kg, targeting dogs and birds in cages. Most of all, as property damage increased due to frequent power outages while moving on the electric wire, the authorities mobilized dedicated search dogs and even tried to combat such as spraying poisoned rats in the forest (▶War against snakes, mobilized even air force to drop’rat bomb’).
Guam’s brown tree snake on the pole. It moved along the electric wire, causing power outages from time to time. Provided by Wikimedia Commons.
Julie Savage, an emeritus professor at Colorado State University in the United States, unexpectedly discovered the unique movement of the snake while studying to protect the micronesian starling, a species endemic to Guam, from a brown tree snake, where a small number of surviving species were preserved. A bird’s nest was placed on a smooth metal cylindrical rod to prevent snakes from climbing, and the brown tree snake climbed on it. A detailed analysis of the video footage revealed that it is a new way of movement that has not been known from snakes until now. Researchers such as Professor Savage reported a new movement of a snake climbing a cylinder in the scientific journal’Current Biology’ on the 12th and named it’Lasso Movement’. “These new methods of migration are contributing to the proliferation and damage of invasive species,” the researchers said.
The brown tree snake is a tree rider. If there are even small bumps, it climbs and climbs a smooth vertical stem. Courtesy of Björn Lardner, US Geological Survey.
There are two ways a snake rides a tree. Usually, the bulge or protruding part of the stem is mounted with strong abdominal muscles. If it is a smooth tree, wind it up in two places, above and below, and then move it upwards by unwinding it in turn. The limitation of this method is that the tree must be thin or long enough to wind the tree twice. If the tree is too large, no matter how much bird nests it has on it, access is impossible. Researchers said, “The noose movement discovered this time is fundamentally different, not a variation of the previously known tree climbing as a method of winding up the tree once and climbing it up.” The way a brown tree snake climbs a cylinder made of metal is to wind the cylinder around a round and make a noose with its tail, and then wriggly and bend in the noose like a wave. The way the lasso moves is not easy. The researchers described the snake ascending a metal cylinder, saying, “The climb was very slow, 4 mm per second, and it slipped frequently, rested frequently, and breathed quickly.” Co-author Bruce Jane, a professor at Colorado State University, said, “It was possible to climb this way, but the snake was pushing its limits.”
The brown tree snake has become famous as a world-class invasive species thanks to its excellent mobility with nowhere to go. Professor Jane said, “This snake climbs vertically no matter how small a bump on its surface, jumps over even the distance between the forest roofs, and can stand upright over two-thirds of its body length.” Cited Papers: Current Biology, DOI: 10.1016/j.cub.2020.11.050 By Jo Hong-seop, staff reporter [email protected]