Scientific Name: Euderma maculatum
Colorado's rarest bat is perhaps its most striking. The spotted bat has enormous pink ears and three large white spots on the black dorsal surface. Measurements of a Colorado specimen are: total length, 119 mm; length of forearm, 52 mm; weight, 13.5 g.
This species may be found in the major canyons along the western border of the state and southeastern Colorado. Its unique appearance should enable correct identification. Any sighting of the spotted bat should be reported to Colorado Paks and Wildlife.
This species is known from scattered localities in western North America and they may be one of the rarest bats in the United States but their ability to avoid standard capture methods suggests they are probably more common than once thought. In Colorado, the spotted bat is known from confirmed records along the canyons of the Western Slope, and acoustic/audible records suggest that the species uses canyon country beyond this area.
The spotted bat has been found in a variety of habitats, including ponderosa pine, pinyon-juniper woodland and shrub desert. Early research suggested that this bat favored ponderosa pine forests, but more recent investigations show that the species uses areas tied closely to cliffs and water. The species appears mostly solitary, forming small nursery colonies or groups in hibernation. Little is known about hibernation or annual movement patterns. Details of mortality are unknown, although known predators include kestrels and owls.
The preferred food of spotted bats is moths. Apparently only the abdomens are eaten as the spotted bat has been observed to remove and discard wings and heads of captured prey. Other food items include beetles, katydids and grasshoppers. Foraging occurs throughout the night, in open habitat, 5-10 m above the ground. The echolocatory calls are audible to humans.
Little is known of the reproductive biology of this species. A single young is born, probably in late May or mid-June. One newborn weighed 4 g, 25 percent of the weight of its mother!