A Pacific coast bat, and a case of mistaken identity
Keen’s myotis is a small, long-eared bat of the Pacific Northwest coast, found from Washington’s outer islands north through coastal British Columbia and into the Alaska panhandle. For decades it carried extra baggage. Biologists lumped it together with the northern long-eared bat, a separate species now known across much of the eastern and central United States, until the two were formally split apart in the 1970s. The confusion wasn’t unreasonable. Both are small brown bats with disproportionately long ears, built for slow, maneuverable flight through cluttered forest. Keen’s myotis is the coastal specialist of the pair. It stays tied to the wet, island-studded fringe of the Northwest, not the interior hardwood forests its eastern relative favors.
Life along a narrow, wet strip of coast
Nearly every documented record of this bat comes from coastal Alaska. Reports cluster hard in early and midsummer, when long northern daylight and an active insect season overlap. Elevation records sit low overall, with most detections under 820 feet. That fits a bat working shoreline forest, river corridors, and low coastal terrain rather than mountain country. It roosts in tree cavities, loose bark, rock crevices, and buildings, and forages along forest edges and over water, where insect activity concentrates. Like most Myotis bats it hunts on the wing at night, using echolocation to track moths, midges, and other flying insects. Across a single night’s foraging, it can take a substantial share of its own body weight in insects.
A slow-breeding bat, built for a long life
Bats live unusually long for animals their size, and Keen’s myotis is no exception. Individuals have been recorded living close to two decades in the wild, a striking figure for an animal that weighs only a fraction of an ounce. That longevity comes paired with a slow reproductive pace. Females bear a single pup a year after roughly seven weeks of gestation, and they don’t reach breeding maturity until close to a year old. A bat population built this way recovers slowly from a bad year. That’s part of why disturbance at roost sites and winter hibernacula matters so much for bats generally, even one the IUCN currently lists as Least Concern.
A hard bat to tell apart, and a hard one to count
Field identification of small Myotis bats is notoriously difficult, even for experienced biologists. The differences between species often come down to fractions of an inch of ear length or subtle skull features, not anything visible on a bat flying past at dusk. That difficulty, combined with the taxonomic confusion with the northern long-eared bat, keeps confirmed records of Keen’s myotis sparse even within its real range. A short list of documented sightings reflects how hard this bat is to confirm, not how scarce it actually is along the coast it calls home.
