Perimyotis subflavus
(F. Cuvier, 1832)

par-E-mI-O-tis sub-flA-vus

An adult Tri-colored Bat.
An adult. Photo by Rob Jagnow.
Image © by Greg Sievert.
Image © by Greg Sievert.
Image © by Greg Sievert.

The Tri-colored Bat is one of the smallest bats in North America. Its distinctive pelage is tricolored dorsally, the base and tip of each hair being dark, these bands separated by a paler middle band. The overall color ranges from yellowish to reddish to brownish gray. Fur covers the anterior third of the tail membrane. The dental formula is incisors 2/3, canine 1/1, premolars 2/2, molars 3/3.
This bat is one of the easiest to recognize. It can be distinguished from other Kansas bats by: 1) a total of 34 teeth, 2) yellowish-brown fur on upper parts with lighter underparts, 3) individual hairs dark at the base and tip with a wide light middle band, 4) reddish skin of the forearm contrasting with black wing membrane, 5) the short, blunt tragus that is less than one half the length of the ear, and 6) the ear, which is noticeably longer than wide.

In Kansas, the species likely occurred only in the East in the past but has dispersed westward with the development of corridors of riparian woodland. The species seemingly is becoming much more common and widespread that it formerly was. A specimen obtained along the Colorado state line in Stanton County is the only bat of this species yet found in far western Kansas and represents one of the westernmost localities of record for the species. It is not known whether this bat (and another seen but not captured) is indicative of 1)inadequate previous sampling (i.e., the bats lived there all the time but no one found them), 2) continued westward expansion of the species in riparian habitat, or 3) migration from some other place.
I am unaware that any fossils of this species have been reported in the scientific literature.The eastern pipistrelle ranges from Nova Scotia to Minnesota and southward to the Yucatan Peninsula. It has been documented in the eastern two-thirds of Kansas. The species seems to be expanding its distribution westward, possibly by taking advantage of man-made structures as roost sites.
Perimyotis subflavus has been reported in Pleistocene deposits in Florida, Kentucky, Missouri, Pennsylvania, Tennessee, Texas, Virginia, and West Virginia. The earliest records of occurrence are late Irvingtonian. 

(, Museum Voucher) (, Observation) (, Literature Record)
Open icons are questionable records; Click on a marker to view details.
  • Occurrence Summary:  
  • 251 Total Records 
  • 186 Museum Vouchers 
  • 65 Other Observations 
Some county occurrences indicated below may be too imprecise to map above.
County Breakdown: County Name (# occurrences):
Atchison (2); Barber (27); Barton (1); Butler (10); Cherokee (25); Comanche (10); Cowley (10); Crawford (2); Doniphan (4); Douglas (4); Ellis (1); Ellsworth (1); Franklin (5); Geary (1); Kiowa (1); Leavenworth (12); Lyon (1); Marshall (84); Rooks (16); Russell (29); Stanton (4); Woodson (1);

Natural History:
The biology of this common bat in winter is relatively well known, but not much is known about its biology in summer. In winter, males and females roost deep in caves or mines, either alone or in small clusters, and often out in plain sight. Condensation on their pelage causes them to glisten when a light is shined on them. In summer, females form maternity colonies in attics of houses, lofts of barns, or hollow trees. These roosts may be several hundred miles from their hibernacula. Less is known about the haunts of males in summer. Presumably many males remain in their cave roosts, but some may roost in thick foliage in trees or elsewhere.
Adults may attain the following dimensions: total length 75-90 mm; length of tail 33-45 mm; length of hind foot 7-10 mm; length of ear 12-14 mm; weight 4-8 g. The oldest known eastern pipistrelle was a male banded in Illinois and recaptured nearly 15 years later.
Food consists largely of moths, beetles, leafhoppers, and small flies. When foraging, this bat can be recognized by its small size and slow, erratic flight. Eastern pipistrelles commonly feed over open pasture. They feed for a while, then roost for much of the night, then feed again.
Documented predators on Tri-colored Bats include large frogs, snakes, Mississippi kites, house cats, hoary bats, and prairie voles. Because of their small size, Tri-colored Bats are less apt to be preyed upon by large predators but more apt to be regarded as prey by small animals.
Mating occurs in autumn before the onset of hibernation. Females carry sperm in their reproductive tract until they emerge from hibernation in early spring. At that time, ovulation and fertilization occurs. Gestation lasts about 60 days, and twin pups are born in June. The pups grow rapidly, and they begin testing their wings at 14 to 21 days of age. They are weaned at about 4 weeks.

Occurrence Activity:
Until recently, this bat was classified as a member of the genus Pipistrellus. The subspecies that occurs in Kansas is Perimyotis subflavus subflavus

1950 Hall, E. R., and W. W. Dalquest A synopsis of the American bats of the genus Pipistrellus. Univ. Kansas Publ. Mus. Nat. Hist., 1:591-602. ():
1952 Cockrum, E. L. Mammals of Kansas. Univ. Kansas Publ. Mus. Nat. Hist. 7:1-303. ():
1955 Hall, E. R Handbook of mammals of Kansas Univ. Kansas Mus. Nat. Hist. Misc. Publ. 7():1-303
1967 Jones, J. K. Jr., E. D. Fleharty, and P. B. Dunnigan The distributional status of bats in Kansas. Univ. Kansas Mus. Nat. Hist. Misc. Publ., 46:1-33. ():
1984 Fujita, M. S., and T. H. Kunz Pipistrellus subflavus Mammalian Species 228():1-6
1999 Wilson, D. E., and S. Ruff Smithsonian Institution Press, Washsington, DC. 1-750pp.
2000 Sparks, D. W., and J. R. Choate Distribution, natural history, conservation status, and biogeography of bats in Kansas Pages 173-228 in Reflections of a Naturalist: Papers Honoring Professor Eugene D. Fleharty Fort Hays State University, Hays, KS. pp.
2000 Sparks, D. W., K. J. Roberts, and C. Jones Vertebrate predators on bats in North America north of Mexico. Pages 229-241 in Reflections of a naturalist: Papers honoring Professor Eugene D. Fleharty. Fort Hays Studies, Special Issue 1, Hays, Kansas. pp.
2008 Timm, R. M., G. R. Pisani, J. R. Choate, N. A. Slade, G. A. Kaufman, and D. W. Kaufman, . pp.
Account Last Updated:
8/21/2018 7:56:06 PM

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