High above the canyons of the Colorado National Monument flies one of the state’s most elusive creatures. A winged crusader in bold costume, he patrols the Grand Valley, pursuing the insect hordes that threaten to overrun us. Concealing himself on high cliffs during the day and emerging only in darkness, little is known about this large-eared hunter and scientists are eager to learn more. They want to know- have you spotted this bat?
The Spotted bat may be Colorado’s most unusual looking mammal. It is one of Colorado’s larger bats, about four and a half inches from nose to tail with a wingspan of about 14 inches, but is distinguished by its outrageously long ears and bold coloration. The fur on the bat’s body is black with three large white spots that suggest two eyes and a mouth. Biologists speculate that these markings may function to scare off predators, as do the eyespots on butterfly wings. Very little is known about the Spotted bat because it is difficult to catch. It roosts in crevices on high cliff faces and it tends to fly above the reach of bat biologist’s nets when hunting for insects. It was not observed in Colorado until 1982 and until recently had only been seen at Dinosaur National Monument and Mesa Verde National Park. Biologists at Colorado Parks and Wildlife suspected that the Spotted bat also occured in our area because the cliffs in the Monument are similar to the habitats where it was found in Mesa Verde- but they had no proof. Then, in 2011, a resident in Mack brought in a dead bat, likely killed by a housecat, that he had found on his property. Biologist Dan Neubaum was very excited. Not only was it a Spotted bat- it was a lactating female, which meant that the bats were breeding in the area.
Oddly enough you are more likely to hear Spotted bats than see them. Many bats emit high-pitched sounds that bounce off objects in their environment and return to the bats ears as echoes. Bats use these echoes to locate objects, like insects, and “see” in the dark- this is called echolocation. Most echolocation calls are so high-pitched that human ears cannot hear them. But two bat species in our area have calls that are low enough in pitch that they are audible to humans, at least those of us with good hearing. If you are down by the Colorado River at nightfall and you think you are hearing bats, do not be alarmed. You aren’t turning into batman or a vampire- you are hearing either a Spotted bat or a Big Free-tailed bat. Their calls are difficult to tell apart unless you have a highly trained ear, but will sound like two small metal balls being repeatedly struck together. The sound will be moving as the bat flies around rather than stationary like most insect sounds.
CPW biologists are hoping to do a survey of the Colorado National Monument soon to get a better picture of the bat species that are present there. In the meantime, Neubaum says they’d love to hear from the public if they have seen a Spotted bat or have any information about bat roosting sites in the area. You can contact him via e-mail at email@example.com or at 255-6192. If you find a bat on the ground, please do not handle it- bats can carry diseases such as rabies. Transmission of rabies from bats to humans is very rare, but may occur when a bat is improperly handled. Overall bats do us much more good than harm- bats consume not only mosquitos, but are also one of the most important predators of insect pests that attack crops. We are lucky to have bats and we are especially lucky to have the Spotted bat. Try and spot one!
An edited version of this article originally appeared in the Grand Junction Daily Sentinel on September 10, 2013. Shortly after it was published, a reader contacted biologist Dan Neubaum to report a reliable sighting (with photographic evidence) of a Spotted Bat near Grand Junction- the second record of the species for Mesa County. Hooray for citizen science!