Myotis lucifugus (Le Conte, 1831)

Little brown bat

A 10-gram insect vacuum, and Ontario's most imperiled bat.

Order: Chiroptera
Family: Vespertilionidae
Group: Wildlife
Ontario status: Native, ENDANGERED in Ontario (white-nose syndrome); protected

Why it matters

ENDANGERED in Ontario and legally protected, colonies in buildings create human-wildlife conflict that must be resolved without harming the bats.

Origin

Native across North America; once Ontario's most abundant bat.

Behavior

Nocturnal; fast, erratic flight close to vegetation and water; reported to eat up to about 1,000 insects in a night.

Living conditions

Maternity colonies in attics and barns; hibernates in caves and mines; needs open water nearby for drinking and insect prey.

Signs of presence

Fine guano piles beneath roost exits
High-pitched chittering at dusk
Bats skimming ponds at twilight

Weaknesses

Devastated by white-nose syndrome, eastern populations crashed over 90%
Tiny size limits roost entry to gaps of about 1.5 cm
Hibernation clusters are countable, and fragile

Myths and facts

Myth All bats carry rabies.
Reality Under 1% of wild bats carry rabies, but because any exposure is serious, every bat contact is treated as a potential exposure. Respect, not panic.

Research notes

Morphology

Body 8-10 cm, wingspan 22-27 cm; weight 5-14 g. Glossy brown fur, dark wing membranes; small mouse-like face.

Diagnostics

Ontario's smallest common bat; rapid fluttering flight.

Easily confused with

Big brown bat (Eptesicus fuscus) Nearly twice the mass with slower, steadier flight; the little brown is the darting one.

Life cycle

Egg: N/A, viviparous (placental mammal)
Nymph or larva: Pup: flight at about 3 weeks
Adult: Sexual maturity about 1 year; lifespan recorded beyond 30 years
Egg to adult: Gestation 50-60 days; weaning about 3 weeks
Generations per year: One pup per year

Development

Single pup; volant at about 3 weeks.

Reproduction

1 pup × 1 litter/year.

Distribution

Native range: North America
Ontario: Native, ENDANGERED under Ontario's Endangered Species Act (white-nose syndrome)
Global: North America only

Ecology

Maternity colonies in buildings; hibernates October, April in caves and mines; forages over water and forest edges; extremely long-lived for its size.

Resistance

Unknown, not applicable; note: no insecticide resistance context, but catastrophic susceptibility to the fungal pathogen Pseudogymnoascus destructans.

IPM implications

ENDANGERED and protected, exclusion only outside maternity season and only by authorized persons; disturbing a maternity colony is an offence under the Endangered Species Act. Conservation framing: this species is in crisis and every colony matters.

Chemical ecology

Olfactory and vocal social cues at roosts; no defensive chemistry.

Genetics and DNA

Reference genome published: Myoluc2.0 (GCF_000147115.1; Broad Institute; Lindblad-Toh et al. 2011, Nature).

Taxonomy

Order Chiroptera, family Vespertilionidae. Myotis lucifugus (Le Conte, 1831).

Open questions

White-nose syndrome tolerance mechanisms; why some hibernacula retain remnant populations.

References

Animal Diversity Web, Myotis lucifugus species account (University of Michigan)
Ontario Ministry species profile, Little brown myotis (Endangered)