Wednesday, March 19, 2014

Invasive Burmese pythons are good navigators and can find their way home

US Geological Survey: Invasive Burmese pythons in South Florida are able to find their way home even when moved far away from their capture locations, a finding that has implications for the spread of the species.  A multi-organizational team of scientists found that when six Burmese pythons were relocated 13-22 miles from their capture locations, the snakes headed straight back home, navigating to within 3 miles of their original capture locations in Everglades National Park.

"Previous studies have shown that many snakes lack the ability to home, yet this study provides evidence that Burmese pythons are capable of homing after they have been displaced --- and they are able to do so at a scale previously undocumented for any snake species," said Shannon Pittman, lead author of the study and a postdoctoral fellow at Davidson College in North Carolina. "Understanding this large-scale navigational ability is critical to understanding the ability of Burmese pythons to expand their geographic range," Pittman added.

To find your way home requires a map sense on the part of the animal, which allows the animal to determine its position in relation to a goal; and a compass sense, which requires access to a reliable compass to maintain orientation toward the goal. The relocated snakes moved faster and straighter than snakes that were not relocated, demonstrating that Burmese pythons have navigational map and compass senses.

The relocated snakes also appeared to use local cues from their release site to determine their position relative to home. Potential cues underlying the map sense in pythons may be olfactory or magnetic that change predictably through space. The compass aspect of their navigational ability could be accomplished through the use of magnetic, celestial, olfactory or polarized light cues, all of which generate a reliable compass sense....

This female Burmese python broke the records for her length - 17 feet, 7 inches - and the number of eggs she contained: 87. She was first captured in Everglades National Park by USGS researchers in the spring of 2012. USGS photo by Catherine Puckett

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