Bats live on every major landmass on Earth except Antarctica. With more than 1,400 species worldwide, they occupy an enormous range of habitats, from tropical rainforests and limestone caves to city attics and the undersides of highway bridges. Where a bat calls home depends on its species, the season, and what shelter is available.
Global Range: Every Continent but One
Bats are found across all major unglaciated landmasses, spanning tropical South America, North and Central America, the Caribbean, Africa (including Madagascar), tropical Asia, temperate Eurasia, and Australia. The greatest concentrations of species sit within the equatorial band between 15°N and 15°S latitude, where three hotspots each support more than 125 species: tropical America, tropical Africa, and the region stretching from Indochina through Sumatra and Borneo.
Diversity drops steadily as you move toward the poles. Between 30°N and 15°S, species counts remain high (above 85 per region). Moderate numbers persist up to about 45°N, roughly the latitude of southern France or Oregon. Beyond 60°N and 45°S, only a handful of species survive, and isolated oceanic islands also have very few or none. Antarctica and the most extreme Arctic regions are the only places bats simply do not exist. This pattern reflects a basic reality: bats depend on insects or fruit, and both become scarce in extreme cold.
Caves, Mines, and Underground Spaces
When most people picture a bat roost, they picture a cave, and for good reason. Caves offer stable temperatures, high humidity, protection from predators, and total darkness. Many species roost deep inside limestone caverns during summer and return to the same caves (or similar underground sites) to hibernate in winter. Abandoned mines serve a nearly identical function. In parts of North America where natural caves are rare, old mine shafts have become critical habitat for hibernating populations.
Not every cave is suitable. Bats are selective about airflow, ceiling texture, and internal temperature. A hibernation site needs to stay cool enough to keep a bat’s metabolism low through winter but warm enough to prevent freezing. A maternity roost, where females raise pups in summer, needs warmer, more stable conditions. That’s why different chambers within the same cave system can host different species or different life stages.
Trees: The Other Major Roost
A large number of bat species never set foot (or wing) in a cave. Tree-roosting bats shelter under peeling bark, inside trunk crevices, and within the hollow cavities of both living and dead trees. A meta-analysis of roost selection studies found that most cavity-roosting and bark-roosting species prefer standing dead trees (called snags) in intermediate stages of decay. These trees offer the right combination of loose bark for cover and internal hollows large enough for a group to cluster together.
Tree diameter matters. Bats that form maternity colonies need large cavities so they can huddle for warmth, which is especially important for newborn pups that can’t yet regulate their own body temperature. Larger, older trees provide those spaces. Only a few studies have documented bats exclusively using cavities in living trees; most tree-roosting bats rely on dead or dying wood. This makes old-growth forests and areas where dead trees are left standing particularly valuable habitat.
Some species skip cavities entirely and roost in foliage. Red bats, for example, hang from leaf stems in the tree canopy, camouflaged to look like dead leaves. Others roost in the rolled leaves of tropical plants or inside the hollow stems of bamboo.
Buildings, Bridges, and Other Human Structures
Buildings mimic many of the features bats look for in natural roosts: stable temperatures, protection from weather, and shelter from predators. Attics are a common choice for maternity colonies because the trapped heat under a roof creates warm, consistent conditions ideal for raising pups. Bats also settle behind shutters, inside wall gaps, under roof tiles, and in the eaves of barns and churches.
Bridges are another major roosting site, particularly in the southern United States. The expansion joints and crevices in concrete bridges can shelter thousands of bats. The Congress Avenue Bridge in Austin, Texas, famously hosts around 1.5 million Mexican free-tailed bats each summer.
For some species, human structures are a backup plan when natural roosts like caves and hollow trees have been lost. For others, buildings have always been part of their habitat mix. Research tracking northern long-eared bats found that use of human-made structures increased as fall progressed and bats began seeking winter shelter. Nearly a quarter of tagged bats in one study hibernated in subterranean spaces beneath houses, using crawlspaces the way they would use a shallow cave.
Colonial vs. Solitary Species
Not all bats share their living space. Species fall roughly into two categories: colonial bats that roost in groups (sometimes massive ones) and solitary bats that roost alone or in very small numbers.
- Colonial species include Mexican free-tailed bats, cave myotis, big brown bats, evening bats, and southeastern myotis. These species form colonies ranging from a few dozen to millions of individuals. They favor caves, mines, and large buildings where space allows for dense clustering.
- Solitary species include eastern red bats, hoary bats, northern and southern yellow bats, and Seminole bats. These tend to roost in tree foliage or under bark, hanging individually or in very small family groups. You’re unlikely to find them in a cave.
Colonial roosting has clear advantages for thermoregulation. A cluster of bats generates shared body heat, which is critical for mothers nursing pups and for species preparing to hibernate. Solitary species compensate by choosing roost sites with good sun exposure or by entering short bouts of torpor (a temporary slowdown in metabolism) to conserve energy on cool days.
Seasonal Shifts in Roosting
Many bats don’t stay in one place year-round. Their housing needs change with the seasons, and they move accordingly.
In spring and summer, females form maternity colonies in warm roosts, whether that’s a sun-heated attic, a tree cavity, or a cave chamber with good thermal properties. Males often roost separately, sometimes in cooler or more exposed spots since they don’t face the same demands of keeping pups warm. Studies of northern long-eared bats found that summer tree roosts tend to be smaller in diameter and more decayed than the trees chosen in fall, suggesting that bats adjust their preferences as temperatures drop and insulation becomes more important.
As fall arrives, bats begin shifting toward winter shelter. Some species migrate. Hoary bats and Mexican free-tailed bats travel hundreds of miles south, following insect availability and warmer weather. Others make much shorter moves, sometimes just a few miles from a summer tree roost to a nearby cave or underground structure for hibernation. Males tend to travel greater distances between roosts than females during these transitional periods.
Hibernation sites, called hibernacula, need to meet strict conditions: cool, stable temperatures and enough humidity to keep a bat’s wing membranes from drying out over months of dormancy. The same cave or mine can serve as a hibernaculum for multiple species, with each choosing slightly different microclimates within the space.
Tropical Bats and Unusual Roosts
In the tropics, where temperatures stay warm year-round, bats have access to roost types that don’t exist in temperate climates. Some species roost inside termite mounds, chewing out small chambers in the hardened walls. Others use the large, pitcher-shaped leaves of tropical plants as natural tents, biting along the leaf’s midrib so it folds downward into a sheltered enclosure. These “tent-making” bats are found across Central and South America and parts of Southeast Asia.
Fruit bats in Africa and Asia often roost in large, exposed tree colonies, hanging from branches in broad daylight. Because many tropical fruit bats are large enough to thermoregulate without needing enclosed spaces, they can afford to roost in the open canopy. Their colonies can number in the hundreds of thousands, turning individual trees into conspicuous, noisy landmarks.
Why Roost Availability Matters
The biggest threat to bat populations in many regions isn’t predation or disease alone. It’s the loss of suitable roosts. Logging removes the large dead trees that cavity-roosting bats depend on. Cave commercialization and disturbance push hibernating bats out of sites they’ve used for generations. Even well-intentioned building renovations can seal off attic spaces that maternity colonies have relied on for decades.
Bat droppings (guano) in enclosed spaces can support the growth of a fungus that causes histoplasmosis, a lung infection in humans. According to the CDC, the spores become airborne when accumulated droppings are disturbed during construction, demolition, or cleanup, and wind can carry them well beyond the immediate site. This health concern sometimes drives people to exclude bats from buildings, which is reasonable when done correctly and timed to avoid trapping flightless pups inside. Bat conservation organizations recommend installing bat houses nearby as alternative roosting sites when evicting bats from a structure, giving the colony somewhere to go rather than simply displacing the problem.