NEBRASKAland Magazine is dedicated to outstanding photography and informative writing with an engaging mix of articles and photos highlighting Nebraska’s outdoor activities, parklands, wildlife, history and people.
Issue link: http://mag.outdoornebraska.gov/i/760935
DECEMBER 2016 • NEBRASKAland 19 By Dan Fogell Winter. Some like it, but I'd venture to bet that like me, most do not. It's cold, windy, and the days are short. We all know someone who heads south every November to get away from it. We call them "snowbirds." Animals don't seem to like it either. Some head south like the snowbirds do. But most have no way of reaching those little latitudes and must find a way to avoid harsh Plains winters. Those most affected are the ectotherms, such as insects, amphibians and reptiles. They can't produce body heat, and they lack fur and feathers – features that give endotherms a thermoregulatory advantage. Thus, they must get out of the cold. A successful overwintering strategy is the limiting factor, determining whether an animal can exist at Nebraska's latitudes. Depending on their strategy, some disappear from the landscape sooner. Some are more cold-tolerant and can wait until the last minute, though none can stay active all winter. And if temperatures are mild, some will still poke their heads out and enjoy the sun. Lizards and Amphibians First down are lizards and amphibians. An unlikely pairing, I agree, but once you know why you'll understand. Insects disappear each winter too, and they happen to be food for lizards and amphibians. Though they could stay out later, they would use crucial energy reserves that could not be replenished. So down they go. Lizards and toads dig deep into sandy soil, and frogs bury themselves in the sediment under water. But on an unseasonably warm day you often see bullfrogs along the water's edge. Turtles Turtles are next. Box turtles dig in just below the surface and stay all winter. Aquatic turtles dive down to the muddy bottoms of lakes and rivers and bury themselves with the frogs. It's important that they get there before ice forms on the surface. On mild days they often emerge and bask for a bit but go back to the mud as the day cools down. Snapping turtles have even been seen walking on top of ice-covered lakes. Snakes Last to go down are the snakes. Older, experienced snakes know how long they can push their luck before the winter cold sets in and may wait until the last possible minute. And while you won't see them on subfreezing days, snakes have been spotted on sunny, 50-something degree winter days. In Nebraska I've seen adult garter snakes every month of the year. Younger snakes are more naïve, and their timing may be off, but they are often the first to enter hibernation. The absolute last snakes to hibernate are babies – the young of the year. Having no experience, they either follow scent trails from other snakes or hibernate wherever they happen to be when it turns cold. Sadly, the latter often results in a suboptimal overwintering site and death. The procession of herpetofauna into their winter hiatus is not random, but rather methodical. Balancing when to enter hibernation with life history decisions like conserving energy, avoiding freezing temperatures and staying warm enough to escape predation involves instinct, experience and even a little luck. The wrong decision can mean the difference between surviving the night and surviving the entire winter. ■ An Annual Hibernation Procession PHOTOS BY DAN FOGELL