Bats

Bats roosting in the administration building at Devils Tower National Monument

NPS photo

Eleven different species of bats have been identified at Devils Tower National Monument. Although some roost on the Tower itself, biologists now know that bats within the park frequent our boulder field and forests at the base, as much or more than the actual formation. The following bats have been identified within the park:

Bats

• Little brown bat (Myotis lucifugus)
• Hoary bat (Lasiurus cinereus)
• Silver-haired bat (Lasionycteris noctivagans)
• Big brown bat (Eptesicus fuscus)
• Townsend's big-eared bat (Corynorhinus townsendii)
• Western long-eared bat (Myotis evotis)
• Fringed myotis (Myotis thysanodes)
• Eastern red bat (Lasiurus borealis)
• Western small-footed bat (Myotis ciliolabrum)
• Northern long-eared bat (Myotis septentrionalis)
• Long-legged myotis (Myotis volans)

Below are some fun facts about the most common bats found at the monument.

 

White-Nose Syndrome (WNS)

Bats across North America are suffering from a disease known as White-Nose Syndrome. WNS is a fungal disease that affects bats during hibernation, causing them to wake up early or more frequently, using the stored energy that helps them survive the winter. The National Park Service (NPS) researches WNS, and you can also find more information from private organizations.

Although WNS does not affect humans directly, our relationship with bats means the disease has serious indirect effects for people. In North America, most bats are insectivorous, meaning they prey on insects. Some bats eat their weight in insects every night. Favorite foods include beetles, moths, crickets and many other crop-destroying pests. Due to their pest control and crop protection, estimates put the value of bats in the billions of dollars.

One of the bat species found at Devils Tower National Monument, the northern long-eared bat, has experienced severe impacts from WNS. It is currently listed as a federally threatened species. Park biologists are studying these creatures and their habitat as part of the greater battle against WNS and bat species decline across our continent.

 

A captured fringed myotis bat.

NPS photo / Dan Wells

Fringed Myotis (Myotis thysanodes)

• Named after the fringed, soft and feathery hairs on its tail membrane; it is the only bat species to have developed these hairs.
• Coloring ranges from a pale buff to a medium brown, with the belly hair being lighter, and wing and tail membranes being much darker.
• Like coniferous forests, such as the ponderosa pine forests at Devils Tower
• Enjoy roosting in trees, caves, mines, rock crevices and buildings
• Become active 1-2 hours after sunset and forage over rivers and streams.
• Baby bats, called pups, are born in June or July; only one pup is born per litter.

 

Many bats, like this little brown bat photographed at New River Gorge National River, will use crevices of trees for roosting.

NPS photo / Mark Graham

Little brown bat (Myotis lucifugus)

• Fur is a glossy brown or reddish brown on the back and upper parts with paler grey fur beneath; wing membranes are dark brown
• Depend on day roosts in tree cavities and rock crevices, which provide safe havens from predators.
• Hunt over water for aquatic insects
• The mating season is in the fall and they have their pups in June

 

Northern long-eared bat, a federally threatened species, captured during mist netting at Devils Tower National Monument

NPS photo / Dan Wells

Northern long-eared bat (Myotis septentrionalis)

• The northern long-eared bat is federally listed as a threatened species under the Endangered Species Act
• The northern long-eared bat is a medium-sized bat with a body length of 3 to 3.7 inches and a wingspan of 9 to 10 inches
• Fur color is medium to dark brown on the back and tawny to pale-brown on the underside
• They usually roost in tree cavities and beneath exfoliating bark in both living trees and dead snags
• Capture prey in flight, but can hunt stationary insects as well
• They have a relatively quiet echolocation call which makes them well suited for sneaking up on prey undetected as well as for maneuvering through cluttered habitats
• Breeding begins in late summer or early fall when males begin to swarm near hibernacula
• Have delayed fertilization: sperm is stored from fall breeding, and fertilizes the egg during spring ovulation
• After fertilization, pregnant females migrate to summer areas where they roost in small colonies and give birth to a single pup

 

Bat Identification

Did you know that bats make up about 20% of all mammal species on earth? Over 1,300 species across the globe means there is a lot of diversity amongst bats. But even members of the same species may differ greatly based on the region where they are found. Park biologists at Devils Tower National Monument work with researchers from various state agencies to identify the specific bat species found at the Tower.