Tricolored 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 “tricolored bat.” The forearms are distinctly pink and contrast strongly with the black wing membranes.
In addition to the coloration described above, note the following:
- The posture typically appears hunched or rounded.
- The ears are small, and the tip of the tragus (the roughly triangular structure in front of the ear hole) is rounded.
- In caves, they are often covered with dewdrops, and they do not form big colonies.
- Compared to other bats, tricolored bats appear as weak fliers, flying with a fluttering motion in an undulating course.
Similar species: Fourteen species of bats occur in Missouri. Missouri's six members of genus Myotis, especially the southeastern myotis (Myotis austroriparius) and northern long-eared myotis (Myotis septentrionalis), are the most similar. The tricolored (not bicolored) fur, pinkish forearms, and rounded tragus help distinguish the tricolored bat from those species.
For more information about Missouri’s bats as a group, visit the Bats page.
Total length: 79–88 mm (3⅛–3½ inches); tail length: 34–44 mm (1⅜–1¾ inches); weight: 3–8 g (about 0.1–0.3 ounce); forearm length: 30–37 mm (about 1⅛–1½ inches); wingspan: 21–26 cm (about 8¼–10¼ inches).
Statewide.
Habitat and Conservation
In Missouri, most tricolored bats hibernate in winter in the most humid and warm parts of caves. They are usually found roosting singly, sometimes in pairs, and rarely in clusters of up to a few to a dozen individuals.
In summer, they roost in trees, in crannies about cliffs or buildings, in barns, or sometimes in high domes of caves. They fly above waterways along the edges of forests and woodlands.
White-nose syndrome is a major threat for this species and has caused dramatic population declines. This is a disease caused by a fungus that infects the skin of cave-dwelling bats, disrupting hibernation, causing bats to deplete their fat reserves before spring, often resulting in starvation.
Do not disturb roosting bats, and do not handle them.
Food
This small bat feeds on tiny insects, particularly flies, moths, wasps, leafhoppers, and beetles, especially aquatic species. They begin feeding about sundown, with other feeding periods toward midnight and near daylight. They generally forage high over watercourses at the forest edge.
Status
A Missouri species of conservation concern, listed as imperiled to extirpation from our state. Its federal status is proposed endangered: it has officially been proposed for listing as endangered; the final ruling has not yet been made.
Between the winters of 2010/2011 and 2016/2017, their populations declined by 86.8 percent, mostly due to white-nose syndrome.
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.
In the wild, tricolored bats can live to be more than 14 years old.
Control
Human Connections
Bats help control insects, some of which are agricultural pests or, like mosquitoes, are annoying or harmful to people.
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.
Bats are one of the few kinds of mammals that people can enjoy watching, but they have suffered from misinformation and superstition for years.
Why the name change? For a century, this species was grouped with many others in genus Pipistrellus, but in the 1980s, researchers concluded it had more in common with the members of genus Myotis, so the new genus Perimyotis ("around Myotis") was created for it. More recently, genetic studies have confirmed its distinctness, so the official common name was changed to reflect the revised taxonomy.
Ecosystem Connections
As predators, bats help to hold insect populations in balance.
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. Without conservation, we may lose many bat species forever.
