Endangered SpeciesA branch of The Humanity Project

Urban Wildlife at Risk

Tricolored Bat

Perimyotis subflavus

One of the smallest bats in eastern North America, devastated by white-nose syndrome and proposed for federal endangered status.

Illustration of a tricolored bat ambassador — very small bat with banded yellowish-brown fur and pinkish forearms — hanging in a cluster of dead oak leaves in a forest at dusk.
Illustrated Species Ambassador — original artwork, not a photograph

Illustrated Species Ambassador

Perry — Tricolored Bat

I'm Perry, an illustrated ambassador for the tricolored bat. I am one of the smallest bats in eastern North America, and my fur is banded in three shades.

One fact worth knowing
The tricolored bat has been devastated by white-nose syndrome and is proposed for federal endangered status.
What I depend on
I depend on warm, humid winter hibernation sites with very stable conditions, and on clusters of dead leaves and Spanish moss for summer roosts.
My greatest threat
My greatest threat is white-nose syndrome.
One way you can help
Observe cave closures and decontaminate gear between caves, and leave dead leaf clusters in trees where it is safe to do so — those are summer roosts.
Urban wildlife at risk →

This ambassador is an original illustration created for this project. It is an educational character, not a documentary image, and its statements follow the sourced record on this page. Artwork and rights record

Why this species matters

The tricolored bat hibernates alone in warm, humid spots — the conditions the white-nose fungus most favors. Its collapse across the eastern United States shows how a species' ordinary habits can become fatal when a new pathogen arrives.

If it disappears: Eastern forests and farmland would lose a substantial consumer of small flying insects, and one of the most widespread bats in the region.

Conservation status

IUCN Red List
VulnerableLast verified 2026-09-08
U.S. Endangered Species Act
Proposed for listing as EndangeredUSFWS proposed listing in 2022 and the final determination has been subject to extension; verify current status.Last verified 2026-09-08
Canada (SARA)
EndangeredLast verified 2026-09-08
State
Listed or of concern in many eastern statesLast verified 2026-09-08

Population

Hibernaculum counts across the affected range have declined by more than 90 percent at many monitored sites since white-nose syndrome arrived.

Trend: Decreasing

As reported: USFWS species status assessment and state hibernaculum surveys

Source: U.S. Fish and Wildlife Service; White-Nose Syndrome Response Team

Uncertainty: This species hibernates singly rather than in clusters, so counts require thorough searching and may undercount.

Historical: Formerly widespread and common across the eastern United States.

Fragmentation: Declines are severe wherever the fungus has arrived; portions of the southern and western range are less affected so far.

Range and distribution

Historic range: Eastern and central North America from southern Canada to Central America.

Current range: The same range, greatly reduced in the affected northeastern and midwestern portion.

Regions occupied

  • Eastern United States
  • Midwest and Texas
  • Southeastern Canada
  • Mexico and Central America

Habitat

Primary habitat: Forested landscapes with water; forages along forest edges and over streams.

Breeding habitat: Females roost in clusters of dead leaves in trees during summer, and in Spanish moss in the south.

Feeding habitat: Catches small flying insects along forest edges and waterways.

Seasonal differences: Hibernates in caves, mines, and, in the south, road culverts.

Habitat dependencies

  • Warm, humid hibernacula with very stable conditions
  • Foliage roosts — clusters of dead leaves and Spanish moss — for summer
  • Forest edges and streams with abundant small insects

Biology and ecology

Consumes large numbers of small night-flying insects in forested and agricultural landscapes.

Important adaptations: Named for the three color bands on each individual hair. Hibernates singly and remains motionless for so long that condensation droplets collect on its fur, which is how the species is often recognized in caves.

Size
About 3 inches long with an 8 to 10 inch wingspan.
Weight
Roughly 4 to 8 grams — one of the smallest bats in North America.
Lifespan
Up to about 15 years.
Diet
Small flying insects — flies, beetles, moths, and leafhoppers.
Reproduction
Mates in autumn with delayed fertilization; gives birth in early summer.
Offspring
Usually twins, unlike most North American bats.
Breeding frequency
Once yearly.
Age at maturity
Females often in their first year.

Primary threats

  • Disease

    White-nose syndrome has caused declines exceeding 90 percent at many monitored hibernacula.

  • Human disturbance

    Disturbance during hibernation causes bats to burn fat reserves they cannot replace in winter.

  • Wind turbines

    Turbine mortality affects this species during migration and dispersal.

  • Habitat loss

    Forest clearing removes summer foliage roosts and foraging edges.

  • Culvert modification

    In the south, culverts used as hibernacula are cleaned, sealed, or replaced.

  • Pesticides

    Insecticide use reduces prey and may cause direct exposure.

  • Climate change

    Changing humidity and temperature in hibernacula affect both bats and fungal growth.

Conservation and recovery

Programs and efforts

  • National White-Nose Syndrome Response Team research and management
  • Hibernaculum protection, gating, and seasonal closure
  • Decontamination protocols for cave visitors and researchers
  • Culvert survey and protection programs in southern states
  • Wind energy operational curtailment during high-risk periods

Protected areas

  • Gated cave and mine hibernacula across the eastern United States
  • National forest and park cave systems

Legal protections

  • Proposed ESA endangered listing
  • Canadian Species at Risk Act
  • State listings
  • Federal cave closure orders

Measurable progress

  • Some southern populations remain relatively stable
  • Curtailment agreements at wind facilities have reduced bat mortality where implemented

Continuing challenges

  • The fungus persists in caves indefinitely
  • Twins per year is still slow recovery after a 90 percent loss
  • Culvert hibernacula are largely unprotected

How people can help

What individuals can do

  • Observe cave closures and decontaminate gear between caves
  • Leave leaf clusters and dead foliage in trees where safe — these are summer roosts
  • Exclude bats from buildings only outside the maternity season, and provide a bat house first

What communities can do

  • Survey and protect road culverts used as winter roosts before maintenance work
  • Support wind energy curtailment agreements

Educational actions

  • Use the condensation droplets on hibernating tricolored bats to teach just how deeply they shut down in winter

Habitat support

  • Maintain forested stream corridors and edge habitat

Organizations and programs to learn about

  • Bat Conservation International
  • USFWS
  • state wildlife agencies
  • White-Nose Syndrome Response Team

Educational notes

  • Named for the three color bands on each individual hair.
  • One of the few North American bats that regularly has twins.
  • Hibernates so deeply that water droplets condense on its fur.

Sources and references