Never go up against a pupfish in a breath-holding contest. This wee swimmer, resident of warm springs near Death Valley in California, can go with almost no oxygen for up to five hours at a time, according to a new study due out this year.
The impressive ability is an adaptation that’s let the desert species hang on despite rapid change to its environment, said researchers this week at the American Physiological Society’s Experimental Biology Meeting.
Too Hot to Handle
Frank van Breukelen and Stanley Hillyard, of the University of Nevada, Las Vegas, wanted to understand how the desert pupfish, a critically endangered species, has coped during the past 10,000 years—the relatively short time it has taken for their home, once a cool, spacious lake, to turn into a series of small pools with temperatures up to 95°F (35°C).
Looking at the evolutionary history of these fish, it’s clear that “they lived in cooler environments not that long ago,” says van Breukelen. It’s just tough luck that things took a turn for the hot: “Sometimes animals live in bad neighborhoods,” he says.
The fish seem to have responded to the change with behavioral shifts, like spending less and less time in the shallower, warmer shelf areas where they breed, the scientists found. Less time making babies surely hasn’t helped the species to thrive. And for the pupfish, which have been hard hit by lost habitat and competition with non-native species, that’s a serious concern.source : http://news.nationalgeographic.com/2015/04/150402-desert-pupfish-death-valley-oxygen-environment-desertification-temperature/?rptregcta=reg_free_np&rptregcampaign=2015012_invitation_ro_all