Back in the late 1800s , scientists stumbled on mysterious , deep , helix - shaped burrows that they dubbed Daimonelix , or Old Nick ’s corkscrews . Some of these date back to 255 million year , and ideas about who the excavators were ranged wildly from giant sponges to plant vine to beaver - similar critter calledPalaeocastor , New Scientist explains . Eventually , skeletons and claw stigma indicated that it was , in fact , the extinct beaver from 20 million yr ago . But without a innovative counterpart , we ’re still not certain why these mystifying , spirally tunnel were created .
Well , déjà vu ! researcher have spotted bodily structure similar to devil ’s corkscrews at the northerly end of Western Australia , and they were made by the yellow - spot monitor lizard ( Varanus panoptes ) . Not only are these the first whorled reptile burrows known , they ’re also the deepest nests ever made by vertebrates . The findings were published in theBiological Journal of the Linnean Societylast week .
A team led bySean Doody from the University of Tennessee , Knoxville , studied 52 of these monitoring equipment lizard burrows . They ’re plugged up with dirt , and at the very terminal , there ’s a nest sleeping room for eggs . The burrows vagabond from one to 3.6 meters ( 3 to 12 metrical unit ) deeply , with the norm at 2.3 meters ( 7.5 feet ) . For compare , giant ocean turtle and crocodilian reptile , New Scientist reports , nest only about half a meter ( 1.5 human foot ) below ground .
They found that , after the top cadence , the ground in the tunnel become more moist with depth . That paint a picture that deep nesting may be an evolutionary reply to egg dehydration during the monitors ’ 8 - month incubation period , which goes into the teetotal time of year . Or perhaps the lizard may be avoiding shallow nesting because of the temperature wavering over the course of the day . Even small changes could be detrimental to evolve embryos . “ Our data point show that this species may have the most static incubation surroundings of any reptile , ” they write .
The team thinks that prehistoric whorled burrows were also used for nesting or rearing young . But why a corkscrew ? " It is pricy to build a helix compared to excavate a consecutive burrow , so there must be a remuneration - off , " DoodytellsNew Scientist . It may have to do with deterring predators or promoting drain during heavy rainfall in the early part of the nesting season . For now , it remains a enigma .
