By Jim Knox
I caught movement darting in and out of the illuminated patch of night sky beneath the stadium lights. The football game was a back-and-forth battle which commanded the attention of nearly all. Still a few fans looked up at the movement and remarked.
“What is that?”
“Is that a bird?”
“It’s a funny color.”
The animal they observed was not a bird and its unusual color grabbed one’s attention. The animal they witnessed was a native Connecticut species seen by few. Inhabiting the entire Eastern United States and Southern Canada, the species is as widespread as it is unique.
Though small, the Eastern Red Bat, Lasiurus borealis, is an eye-catching creature. With a wingspan of just 13 inches, a body length of just four and a half inches, and a weight of ¼ to ½ ounce, this species is understandably classified as a microbat. Yet its diminutive form cannot conceal its visual effect. While females display red silky fur highlighted by frosted gray tones and white shoulder patches, the males possess dense, cinnamon or brick red coats. This bright coloration is thought to aid the bats in camouflaging their form among the leaf litter.
Why would bats possibly hide within leaf litter? The answer might surprise you. Though Red Bats roost in trees—where they resemble dead leaves—when the mercury plunges, they adapt to the cold in a novel, and highly efficient manner. These adaptable mammals nestle within the fallen leaves of the deciduous forests. While even shallow layers of leaves enable the bats to save substantial metabolic energy when the fall nights drop below freezing, the real savings come when the bats “dig deep.” In deeper leaf layers the bats gain an energy saving of between 200% to 300%, and when roosting under leaf litter with snow cover, they can gain an astounding metabolic energy savings of more than 500%!
Though risky in terms of potential predator encounters, the strategy pays off for the Red Bat—one of North America’s most widespread and common bats. Far from alone, the Red Bat’s kin represent no less than half a dozen closely related species inhabiting the New World from Southern Canada to Cuba to Argentina.
Far from just another pretty face, the Red Bat earns its keep in terms of predator / prey equilibrium. As an extremely fast flyer attaining flight speeds of 40 miles per hour, this agile little bat can overtake its insect prey in flight. Prey species include many regarded as agricultural, forest and human health pest species. Gypsy moths, beetles, spittlebugs, and mosquitoes all find themselves on the menu.
Though most bats raise a single offspring or sometimes a pair, known as pups, as the only known bat species with four teats, the Red Bat can raise 2-4 young. It is this prolific ability that enables the Red Bat to counter the many hungry predators within their vast range. With Opossums, Great Horned Owls, Screech Owls, Sharp-shinned Hawks, and even Blue Jays to avoid, the Red Bat will wield every survival advantage it possesses.
Though singular in its survival strategy, this small mammal possesses one more trait which sets it apart from the competition, and it is no small matter. Though the Red Bat can carry the spores of the deadly White-nose Syndrome fungus Pseudogymnoascus destructans, biologists have yet to discover a Red Bat with symptoms of the disease. With this disease reducing some bat populations by more than 90%, it represents a serious threat to bat survival. Though mammalogists have made progress in combating this disease in terms of habitat modifications and a vaccine, nature may already have found the solution in the genetics of this modest creature.
With bats representing nearly ¼ of the world’s 6,400 known mammal species, you can’t argue with success. This incredibly diverse order of mammals has successfully colonized all the world’s major land masses with the exception of the polar regions, and isolated island groups. As the world’s only flying mammals, bats can migrate with greater ease, over greater distances, than their earthbound cousins. They can also simply access better habitat more readily. It is this adaptability that serves them well in a world modified by human activity. This diversity/adaptability aspect makes bats excellent study subjects.
So, the next time you’re out for a hike and you look up at that single leaf among the greenery, or the thousands of leaves at your feet, consider our neighbor with the bright red coat. Whether you seek beauty, scientific knowledge, or natural equilibrium, she might just have the answer.
