Bats at El Malpais

Mexican free-tailed bats exiting Bat Cave
Bat Outflight

Bat Outflight

The natural phenomenon of watching thousands of bats emerge from their cave roost and rise into the twilight in search of food is a spectacular sight. You can witness this exciting natural event during the summer months.


How to See Bats in the Park

The best way to see bats in the park is by observing outflights at Bat Cave (in the El Calderon Area). During the summer, tens of thousands of Brazilian free-tailed bats (also known as Mexican free-tailed) use Bat Cave as a day roost, emerging for their nightly feedings just after sunset. On some Saturdays there will be a Ranger guided tour starting one hour before sunset at the El Calderon parking area, but feel free to experience the outflight on your own. We ask that you be quiet and speak in hushed voices as you near the collapse. Refrain from using flash photography and never shine your lights on the bats. Please leave pets at home and remember to bring a flashlight for the walk back to your car. There are many caves in our park that bats can use and many factors (such as weather) that may affect their activity, so be aware that the number of bats emerging will vary. The peak of the season occurs during the first week of July.

For more information about guided outflights call the El Malpais Visitor Center at (505) 876-2783.

Do not go looking for bats in caves! During different seasons our caves close to protect the bats. Bats are very sensitive to disturbances. When bats are disturbed during their winter hibernation, they use up their valuable fat stores and can starve to death. Many caves are used as maternity colonies in the summer. Disturbing a maternity colony can cause bats to attempt to find new roost sites which can be fatal for both mothers and pups. Please respect cave closures.

If you are caving in one of the caves that are open to recreation and you see a bat, leave it alone. Try to be as quiet as possible, do not shine lights directly on it, do not touch it, and do your best not to wake it up. If it seems like your continued activity in the cave is disturbing the bat (it starts to move), quietly exit the cave. Likewise, if a bat is flying around, quietly make your way back to the mouth of the cave.

White-nose Syndrome

A number of bat species are in peril from the fungus Pseudogymnoacus destructans, commonly known as White-nose Syndrome (WNS). WNS was first discovered in the US during the winter of 2006-2007. Although this deadly fungus has yet to appear in New Mexico, it is spreading rapidly from the east coast where it has caused the death of more than 6 million of bats.

White-nose Syndrome is caused when fungus grows on the wings, ears, and around the nose of bats while they are huddled in caves for the winter. The fungus irritates the bats during hibernation, causing them to frequently wake while they should be in torpor (their dormant hibernating state), increase their metabolism, and use up their limited winter fat stores. The bats become hungry and dehydrated and eventually die of starvation. Because smaller bats have a smaller fat reserve, the smaller species are most affected by White-nose Syndrome. Bats that survive the winter with the fungus may be left with skin damage ranging from light scarring to holes in their wing membranes.

The fungus is most deadly in the winter when the bats stay in the cool moist cave environment and pass the fungus on to one another. During the summer as the bats forage in the dry night air the fungus cannot survive.Once the White-nose fungus is introduced to a cave there's no good way to get rid of it. Bats will continue to return to their favorite caves, grow this fungus, and spread it to other roosting sites.

What You Can Do To Help

In order to keep our caves safe from this deadly fungus we are taking a few precautions. When you go to the El Malpais Visitor Center to pick up your FREE caving permit, they will ask you a few questions about your caving gear. If you have used any of your gear in a cave in a state where WNS occurs, you will not be able to use your equipment here at El Malpais. If you have used your gear in a cave outside of our park, they will ask you to please decontaminate them. We will provide the supplies to clean your gear at no cost to you. This is a simple process that will help us to avoid the spread of the white-nose fungus by humans. If you would prefer to clean your gear at home you may follow the instructions from USFWS here.

You can find out more about White-nose Syndrome and what is being done to fight it by clicking here.

Common Bat Myths

Vampire Bats

There are only three species of bat that drink blood (called hematophagy), but you will not find any in our park. They live in Central and South America and will rarely, if ever, reach the continental US. These bats are very unlikely to drink human blood; they prefer large, slow-moving animals such as cattle. They do not suck blood; they make a small incision with their modified canine teeth and then lap up the blood that drips out. Their long hind legs lack a flight membrane allowing them to crawl, run, and jump on the ground so that they may sneak up on their sleeping prey. Their saliva contains a natural anti-coagulant that has been used to treat victims of strokes and heart attacks.

"Blind as a Bat"

No bat is completely blind. At night and especially in caves, bats depend on echolocation to visualize their environment, but they use their eyes to see the area beyond that range. All of the bats in the US have dichromatic vision, which means that they are red/green colorblind and probably see the world in shades of blue and yellow. It has been suggested that dichromatic vision actually helps bats detect colors better in low light conditions. Some bats have even been known to see colors in the ultraviolet spectrum and others use polarized light on the horizon to visually orient themselves.

Bats in Your Hair

Bats are agile fliers and will avoid you if at all possible. The human head is not a particularly useful roosting site.

Bats are Disease Ridden

Although it is required that anyone handling bats have a rabies vaccine the vast majority of bats are perfectly healthy. Even in regions where rabies is endemic, there is only a 0.5% chance that a bat will carry the disease. However, if you see a bat on the ground or flying in the daylight, DO NOT TOUCH IT. Bats exhibiting abnormal behavior are more likely to be sick. This is true, not just for bats, but any animal you may encounter in the park.

Bats Are Just Flying Rats

Bats are in the Order Chiroptera (which translates to "hand-wing"). Rodents are in the Order Rodentia. One of the closest orders to bats is Carnivora (cats, dogs, bears, etc.) while one of the closest orders to rodents is Primates (monkeys, apes, and humans). Long story short, you are more closely related to rats than bats are.


Bats emit high-frequency pulses of sound, typically inaudible to humans, in order to navigate and investigate their environments. The sounds are emitted through either the nose or the mouth depending on the taxonomic family. You can often tell how a bat emits its call by looking at its face, a goofy looking nose means it is a nasal emitter, wrinkly lips means oral emitter. The returning sound is then picked up by the large ears of the bat. The size of the bat generally corresponds with frequency of the sound the bat makes. Larger bats usually have a lower frequency sound and the smaller bats have a higher frequency. The higher the frequency the bat emits, the smaller the bugs that can be detected.

Hibernation and Migration

During the winter when there is less food available, many bats will either migrate to warmer regions or hibernate. A good hibernation roost, or hibernacula, can be found in caves, abandoned mines, or other protective shelters within forests. In late fall, when proper hibernacula have been reached bats will enter a state of torpor, during which body temperature drops, their heart rate slows, and metabolic activities are greatly reduced. Hibernation typically lasts 5-6 months in which the bats must survive on a small amount of fat storage.

Protecting hibernacula is one of the most important aspects of bat conservation. Each species has its own preferred roost. Some prefer to be deep in the caves. Some hibernate closer to the mouth. Others find protection in trees. Each group of bats has particular hibernacula that they will return to over many generations. If hibernacula are destroyed or a specific characteristic of the microclimate changed, the bats may not roost there and may die before other suitable hibernacula are found. Once bats are settled into their hibernacula and have entered torpor, it is very important that they not be disturbed. If a bat wakes up during hibernation, its metabolism will increase and it will use up its precious fat stores much quicker. Periodically bats in hibernation will awaken on their own to drink, urinate, shift, and mate, but excessive disturbances can be deadly.

What they do and where they go depends on not only species, but individual populations. The Brazilian free-tailed bats that spend the summer at El Malpais have migrated from the Sierra Madre Mountain range in Mexico. The free-tailed bats from western Arizona spend their winters in Baja, Mexico. Free-tailed bats in Eastern Texas do not migrate at all, but will shift roost sites throughout the season.

Bats at El Malpais

Brazilian free-tailed bat (Tadarida brasiliensis)

§ Migratory

§ Habitat: Multiple, throughout the Southern US, Central, and South America (but not including the Amazon rainforest)

§ Roosts: caves in the Southwest, man-made structures in the Southeast

§ Diet: small moths and beetles

§ Wingspan: 11-14 inches

§ Females form maternity colonies and give birth to one pup in late spring/early summer

§ Thought to be the most common mammal in North America because of their large colony sizes.

Big brown bat (Eptesicus fuscus)

§ Hibernate in caves or other underground structures

§ Habitat: common throughout the US

§ Roosts: mostly in man-made structures (i.e. attics, barns) or hollow trees

§ Diet: beetles, ants, flies, mosquitoes, mayflies, stoneflies, and other insects

§ Wingspan: 13-15 inches

§ Pups born in early June—twins in eastern US and single pups in the west (they live in nursery colonies of 20-300 bats for the first month)

§ Common

Western small-footed myotis (Myotis ciliolabrum)

§ Hibernates in caves or mines

§ Habitat: common along wooded waterways in rough terrain or grasslands in Alberta, occurs in deciduous and coniferous forests in Nebraska

§ Roosts: solitary in rock crevices, erosion crevices in soil, stream banks, caves, tunnels, buildings, and under loose tree bark

§ Diet: moths, flies, true bugs, and beetles

§ Wingspan: 8-9 inches

§ One pup (occasionally twins) born each year in May or June

§ Proposed for listing as threatened or endangered

Long-eared myotis (Myotis evotis)

§ Migrate short distances to hibernate in caves or mines

§ Habitat: mostly forested areas, chaparral, and shrubland

§ Roosts: abandoned buildings, hollow trees, loose slabs of bark, timbers of unused railroad trestles, caves and mines, fissures of cliffs, and sinkholes

§ Diet: moths, beetles, flies, net-winged insects, and true bugs

§ Wingspan: 10-11 inches

§ One pup in late June or early July

§ Proposed for listing as threatened or endangered

California myotis (Myotis californicus)

§ Hibernate in caves or mines (though some in warm climate stay active all winter)

§ Habitat: humid coastal forest to the semidesert, usually occurring near water in arid regions

§ Roosts: rock crevices, hollow trees, spaces under loose bark, and in buildings

§ Diet: small flying insects (primarily flies, moths, and beetles)

§ Wingspan: 9 inches (one of the smallest bats in the US)

§ Breeding occurs in the fall and one pup is born in July

§ Common

Fringed myotis (Myotis thysanodes)

§ Migrate to hibernacula

§ Habitat: varies from desert-scrub to fir-pine, oak and most commonly used pinyon woodlands

§ Roosts: caves, mines, buildings

§ Diet: beetles and moths

§ Wingspan: 11-23 inches

§ Breed in the fall, one pup in late June or early July

§ Proposed for listing as threatened or endangered

Long-legged myotis (Myotis volans)

§ Hibernate over winter in caves and mine tunnels

§ Habitat: forested mountainous regions

§ Roosts: trees, rock crevices, cracks, crevices in stream banks and buildings

§ Diet: moths and other soft-bodied insects (flies, termites, lacewings, wasps, true bugs, leafhoppers, and small beetles)

§ Wingspan: 10-11 inches

§ One pup born in July

§ Proposed for listing as threatened or endangered

Townsend’s big-eared bat (Corynorhinus townsendii)

§ Hibernates in caves and mines

§ Habitat: rocky forested areas throughout the western US

§ Roosts: caves or mines

§ Diet: believed to feed entirely on moths

§ Wingspan: 12-13 inches

§ Breed in the fall, one baby born in June

§ Has a few endangered subspecies, the Ozarks big-eared and Virginia big-eared bats

Canyon bat (Parastrellus hesperus)

§ Hibernates in mines, caves, and rock crevices

§ Habitat: primarily a desrt species (rocky canyons, cliffs, outcroppings in creosote bush flats

§ Roosts: single or in small groups in rock crevices, beneath rocks, in burrows, mines, or buildings

§ Diet: caddisflies, stoneflies, moths, small beetles, leaf and stilt bugs leafhoppers, flies, mosquitoes, ants, and wasps

§ Wingspan: 7-9 inches (one of the smallest US bats)

§ Twins born in June or July

§ Common

Pallid bat (Antrozous pallidus)

§ Hibernate in deep crevices or caves

§ Habitat: arid regions with rocky outcroppings, particularly near water

§ Roosts: usually roosts in small colonies (20+ individuals) in rock crevices, buildings, and sometimes in caves, mines, rock piles, or tree cavities

§ Diet: flightless arthropods (scorpions, crickets, solpugids), ground-roving insects (darkling ground beetles, scarab beetles, predacious ground beetles, carrion beetles, short-horned grasshoppers), prey gleaned from vegetation (cicadas, katydids, praying mantises, long-horned beetles, sphingid moths), and occasionally lizards and rodents

§ Wingspan: 15-16 inches

§ One pup or twins born in May or June

§ Common

Hoary bat (Lasiurus cinereus)

§ Migratory

§ Habitat: coniferous forests

§ Roosts: day roosts in tree foliage

§ Diet: moths, true bugs, mosquitoes, other insects, and occasionally other bats

§ Wingspan: 13-16 inches

§ One pup or twins born from mid-May to early-July

§ Most widespread bat in the Americas (common)

Silver-haired bat (Lasionycteris noctivagans)

§ Solitary migrant

§ Habitat: forested regions

§ Roosts: roost in trees (typically under loose tree bark, but also in woodpecker holes and bird nests) or man-made structures/forages over woodland ponds and streams

§ Diet: moths, true bugs, flies, mosquitoes, termites, and beetles

§ Hibernate in trees, buildings, rock crevices, and similarly protected shelters

§ Wingspan: 11-12 inches

§ Usually twins born in June or early July

§ Relatively uncommon

Big Free-tailed bat (Nyctinomops macrotis)

§ Migratory

§ Habitat: rocky areas

§ Roosts: roost in crevices on high cliffs and potentially in buildings

§ Diet: primarily large moths, also crickets, flying ants, stinkbugs, and leafhoppers

§ Wingspan: 17 inches

§ One pup born in June or July

§ Uncommon, considered to be listed as threatened or endangered

Spotted bat (Euderma maculatum)

§ Migratory

§ Habitat: often rough, rocky, semiarid, or arid terrain ranging from ponderosa pine forest to scrub country and open desert

§ Roosts: roosts often on high cliffs or tall trees

§ Diet: primarily moths

§ Wingspan: 13-14 inches

§ One pup born in June

§ One of the rarest bats in North America (proposed for listing as threatened or endangered)

Bats are the only mammal capable of true sustained flight. They make up around 20% of all mammals, with more than 1,200 species of bats in the world. As with all mammals, bats give live birth, produce milk, and have fur.

Bats are a valuable resource and provide great benefits to humans. Roughly 70% of bats are insectivorous and are the only major predator of night-flying insects. They help reduce the mosquito population and the spread of diseases such as the West Nile Virus and malaria. They also consume pest insects that would destroy crops if not controlled by the local bat colonies. Bats will typically eat half of their body weight in insects in a single night and a nursing female may eat twice that in order to sustain the needs of herself and her pup.

Some species are pollen and nectar feeders. These bats serve as major pollinators of many plants used by humans including bananas, mangoes, figs, cashews, and agave (which is used to make tequila). Fruit bats also act as seed dispersers, generally eating over-ripened fruit, which can be a big benefit to fruit farmers. They are, however, not typically found in the US. Bat feces (also known as "guano") is an important ingredient used to make organic fertilizer, because it is high in phosphorus and nitrates.

Last updated: July 19, 2020

Contact the Park

Mailing Address:

1900 E. Santa Fe Ave.
Grants, NM 87020


(505) 876-2783
This number calls the El Malpais National Monument Visitor Center. Rangers are on staff from 9:00 AM to 5:00 PM to answer calls.

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