Tri-Colored Bat

Perimyotis subflavus (formerly Pipistrellus subflavus)
Other Common Name
Eastern Pipistrelle; Tricolored Bat
Family

Vespertilionidae (evening bats) in the order Chiroptera

Description

Tri-colored bats, formerly called eastern pipistrelles, are relatively small and overall look pale yellowish or pale reddish brown. The main hairs, when separated by blowing into the fur, are seen to be dark gray at the base, then broadly banded with yellowish brown, and tipped with dark brown; the three-colored hairs explain the name "tri-colored bat." In caves, they are often covered with dew drops. This species is usually found roosting singly, sometimes in pairs, and rarely in clusters of up to a few to a dozen bats. The forearms are distinctly pink and contrast strongly with the black wing membranes. Ears are small, and the tip of the tragus (the roughly triangular structure in front of the ear hole) is rounded. They posture typically appears hunched or rounded. They are common in winter.

Size

Total length: 3–3½ inches; tail length: 1½–1¾ inches; weight: 1/10–2/7 ounces (2–8 g).

Tricolored Bat

A fuzzy tan bat clings to a cave ceiling by one foot.
Tricolored bat in Pike County
Tri-colored bat
Habitat and conservation

Bats of this species can be found hibernating singly in most caves in Missouri. In our state, most tri-colored bats hibernate in winter in the most humid and warm parts of caves. In summer, they roost in trees, in crannies about cliffs or buildings, in barns, or sometimes in high domes of caves. Do not disturb roosting bats, and do not handle them. One of the few kinds of mammals that people can watch, bats have suffered from misinformation and superstition for years.

Foods

This small bat feeds on tiny insects, particularly flies, moths, wasps, leafhoppers, and beetles, many of which are aquatic forms. Compared to other bats, tri-colored bats appear weak fliers, flying with a fluttering motion in an undulating course. They begin feeding about sundown, with other feeding periods toward midnight and near daylight. They generally forage high over watercourses at the forest edge.

image of Tricolored Bat Eastern Pipistrelle Distribution Map
Distribution in Missouri

Statewide.

Status

Common, but declining.

Life cycle

Mating occurs in fall, intermittently throughout winter, and again in spring. Relatively small maternity colonies start forming in mid-April. The 1 or 2 (rarely 3) young are born from late May to mid-July, after a gestation period of at least 44–60 days. The young are able to fly at about 4 weeks of age. They probably do not mate in the year of their birth.

Human connections

Bats help control insects, some of which are agricultural pests or are annoying to people (such as mosquitoes). Bats have contributed much to human knowledge through scientific studies of their echolocation, biology, and physiology. Bats are protected by both state and federal laws.

Ecosystem connections

As predators, bats help to hold insect populations in balance; also, many forms of cave-dwelling life depend on the nutrients brought in by bats and released from their guano (feces). The only mammals capable of true flight, bats are greatly important in the natural scheme of things.