one in five reptiles is threatened with extinction mostly caused by humans

“we would lose a combined 15.6 billion years of evolutionary history if each of the 1,829 threatened reptiles became extinct,” co-the study’s author neil cox told the guardian . “this is evolution that we could never get back. it would be a devastating loss.”

reptiles are at risk because of humans

climate change also reduces the amount of time reptiles can forage for food, skewing natural sex ratios in some species that have temperature-dependent sex determination. (turtles, for instance, are born male if the eggs incubate below 27.7 degrees celsius, and female if they’re above 30.9; a temperature in the middle will yield a mix of male and female babies. a changing climate could decrease the number of male turtles born, making it more difficult for the species to reproduce.)

researchers used data from 24 countries over a 15-year period, following the international union for conservation of nature’s red list of threatened species to determine the relative threat to 10,196 reptile species.

of all of those animals, they found that 21.1 per cent faced extinction. fifty-seven per cent of turtles and 50 per cent of crocodiles are threatened, compared to 19 per cent of squamates , a reptilian group that includes snakes, lizards, iguanas, chameleons and other species that shed their skin and have flexible skulls and jaws. within the squamate group, iguanas, xenosaurid lizards, and certain kinds of snakes (shield-tailed and tropidophiid) are the most at risk. (salamanders, which also face a high extinction rate in the 57 per cent range, are often mistaken for reptiles but are actually amphibians, meaning they breathe through gills rather than lungs.)

“reptiles, to many people, are not charismatic, and there’s just been a lot more focus on the furry or feathery species of vertebrates for conservation,” bruce young, chief zoologist and senior conservation scientist at conservation nonprofit natureserve, which in part led the study, told cnn .

reptiles “help disperse seeds, especially in island environments,” hoffmann said . “we’ve also achieved many medical advances from studies of reptiles. snake venom, for example, has resulted in critical drug discoveries, including for treating hypertension .”