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/708333
56 NEBRASKAland • AUGUST-SEPTEMBER 2016 Bat 101 Bats are the only mammals in the world that truly fly. They navigate the skies on wings that possess a bone structure resembling a human arm and hand. Stretched between elongated finger bones to its hind legs, and between its legs, is a thin membrane of elastic skin that forms the wing surface when a bat's arms and fingers are extended. Extending from the leading edge of the wing is a clawed thumb that, with its hind feet, allows a bat to cling and climb. Bats fly well and can make rapid changes in flight to catch insects or avoid obstacles. To drink, they swoop down over a stream, pond or stock tank, open their mouths and skim water from the surface. They navigate the night skies not with vision, but with echolocation. Many species emit high-frequency sounds and, with their sensitive ears, listen for the echoes that bounce back from objects in front of them, a technique man has replicated in sonar. During the day most species roost in mines, caves, trees, buildings, cracks in rock faces or other tight, dark places. Some forest species such as red and hoary bats are happy to roost in trees in broad daylight. The smallest of Nebraska's bats, the eastern pipistrelle and western small- footed bat, weigh about one-sixth of an ounce, equal to that of a nickel, and have a wingspan of about 8 inches. The largest, the hoary bat, can weigh up to 1 1 ⁄4 ounces and has a wingspan of 13 inches. A bat's body is covered with soft, dense fur. Some have furred tails they can wrap around their bodies to conserve heat. Bats are warm-blooded mammals that give birth to live young and nurse them with milk. Bats mate in the fall, winter or early spring. Females of some species delay fertilization by storing the male's sperm until they ovulate in late winter or spring. Gestation lasts one to two months. Females can carry their young to new roost sites until they can fly on their own at about four weeks of age, and wean them by six weeks. Some species form maternity colonies of a handful to hundreds of thousands of bats. Some people say bats are just winged mice. But unlike mice and most small mammals, which live short lives and reproduce rapidly, most bats produce just one young per year, some up to four, throughout their lives. They can live 10 to 20 years, and the oldest known bat lived to age 35. While a few of the world's 1,100 species of bats eat fruit, nectar, blood, fish or small mammals, most, including all of Nebraska's species and nearly all of the 50 or so found in the United States, are insectivores. As such, bats found in colder climates such as Nebraska have two methods of surviving the months when insects are not available. Some hibernate, primarily in caves or mines, from mid- fall until insects emerge in the spring. Others migrate to warmer climates, returning in the spring. As is the case with wild animals, Nebraska is a crossroads for bats. While some are found statewide, including the resident big brown bat, others are at the eastern or western edge of their range here. The resident long-legged bat, for example, is found only in the Pine Ridge. The ranges of some bats, like many other mammals, are shifting. The migratory evening bat, once found only in southeastern Nebraska, is spreading westward along the forests that have grown along rivers since fire was controlled and rivers dammed. In summer, most bats roost in Keith Geluso, a professor at the University of Nebraska at Kearney, removes a big brown bat from a mist net he set above Soldier Creek at Fort Robinson State Park as part of a population survey of bats in the Pine Ridge he conducted for the U.S. Forest Service.