is home to 28 species of bats, more than almost any other state. Bats
are the only true flying mammals and are valuable human allies.
Worldwide, they are primary predators of vast numbers of insect pests,
saving farmers and foresters billions of dollars annually and helping to
control insect-spread human diseases. For example, large colonies of
Mexican free-tailed bats (Tadarida brasiliensis) eat hundreds of tons of moths each week, especially the moths that prey on cotton crops.
bats play key roles in keeping insect populations in balance, they are
North America's most rapidly declining land mammals. Declines are often
caused by human fear and persecution, and each of us can help by
learning how to live with these animals.
Description and Habits
- Fist-sized or smaller, with short fur and thin wings, many have large ears
- Brown, gray, yellow, red, some with frost-tipped fur, spots or dark eye mask
- Similar eyesight to humans
- Many eat insects in flight and can eat more than 1,000 insects in an hour, including mosquitoes
- Some species drink nectar and can drain a hummingbird feeder overnight
- Use echolocation, emitting sound to locate solid objects
upside-down to rest in dark, secluded "roosts” during daytime; leave
roost to forage for food at night and may temporarily roost to digest
food and groom
- Some hibernate during winter (October through April), and some stay active year-round
- Most have one or two live young each year, usually between May and July
- Females nurse offspring and form maternity roosts that can contain hundreds or thousands of bats
Potential Conflicts with Humans and Pets
While some people appreciate bats and the ways they benefit us, others
fear bats because a small percentage of them can expose humans and pets
to rabies. Bats should always be kept out of places where people live
indoors. Bat guano (feces) can present disease and odor problems.
However, bats are generally harmless to humans and are extremely
beneficial for controlling insects and mosquitoes and pollinating some
plants. Bats are vulnerable to disturbances by people because of their
roosting habits and slow reproductive rate.
What Attracts Them?
If bats are in an area, it is probably because they are finding food, water or shelter.
- Food can include
insects that congregate in areas near lights, agricultural or playing
fields, ponds or other water sources. Nectar-feeding bats may be
attracted to flowering agaves and hummingbird feeders.
- Water sources can include any pool, pond or lake with a long flying corridor that bats can skim.
can include rough surfaces for hanging. A bump of only 1/16 inch is
enough. Bats can squeeze into holes as small as 3/8 inch and are
attracted to spaces inside buildings and attics, under bridges, in
culverts, behind siding on buildings, in palm trees, and under eaves and
porch or patio awnings.
What Should I Do?
Bats should never be allowed to remain in human living areas. However,
bats roosting on the porch, in the yard, or in a bat house are far more
beneficial than harmful, and the small amount of guano can be cleaned
up or used as fertilizer, in exchange for the reduction in flying
insects and mosquitoes. The following ideas can help you coexist with
bats or exclude them if necessary.
In an emergency:
a person or pet is bitten by a bat, immediately wash the wound, attempt
to capture the animal while wearing leather gloves, and contact your
local county health department right away. The bat may have rabies and must be tested to determine whether the bite victim needs rabies shots.
- If a bat is in human possession, please call your local Arizona Game and Fish Department regional office during
weekday business hours. After hours and weekends, call the Arizona Game
and Fish Department radio dispatcher at (623) 236-7201.
Solutions to common problems:
A bat inside a building is probably just lost.
the interior doors to confine the animal to one room or section of the
building (making sure all pets and children are out of the area).
- After dark, open all doors and windows to let the bat fly outside on its own.
- Turn inside lights off to help bats find open windows and doors.
the bat does not leave on its own after several hours, put on leather
gloves, and then place a box, coffee can or glass jar over the bat when
it is on a wall. Slide a lid or piece of stiff paper over the top; then
release the bat outside while it is still dark.
the bat up high to allow it to fly away, or place it on the edge of a
tall building, fence or tree branch (otherwise it may not be able to fly
up from the ground).
- Handle bats gently to avoid injury to the bat, and never handle bats with your bare hands.
- If a bat cannot leave an indoor space on its own or be let out easily, please call awildlife control business.
- Bat on a building during the day
bats may roost temporarily as they move through an area. This happens
most often during spring and fall. Bats roost in cracks, crevices, beams
- These bats will usually only be around for a few days, or maybe up to a week or so, and it is best to leave them alone.
- After the bats move on, seal cracks or holes with foam, weather stripping or other materials if desired.
- Never exclude bats between May and September unless you are sure no young are left behind.
bats are left alone all night while their mothers search for food and
should not be disturbed. If the mothers do not appear by daylight,
contact either the Arizona Game and Fish Department Wildlife Center at Adobe Mountain at (623) 582-9806 or a licensed wildlife rehabilitator.
- Bat on a building at night
Bats roosting during the
night are generally digesting insects caught nearby and will leave
within a few hours. "Night roosting” bats are attracted to porches,
patios and overhangs.
up the guano during the day, and then check the area the next morning
to find out if the bats are indeed night roosting or if a day roost is
- Guano makes an excellent garden fertilizer; place sand beneath the roost to make cleanup easier.
- Discourage unwanted night-roosting bats by:
- Changing temperature - leave a light on in the area during the night;
- Changing humidity - leave a fan on overnight to blow air directly toward the bat roost site;
- Tying mylar balloons so they bump against the roosting area;
- Covering wood, stucco or problem areas with metal or plastic sheeting.
- Bat on the ground
A bat on the ground that acts sick or unable to move may have rabies.
a bat is on the ground and sick or unable to move, then leave it alone,
keep pets and children away, and contact your local county health
- Most bats cannot fly up from ground level. If a bat has been knocked down during a storm and does not seem sick or injured, then use a stick to gently raise it to a tree limb. At nightfall, the bat should fly away.
a bat is injured or a baby bat is on the ground, then contact the local
Arizona Game and Fish Department office for instructions. NEVER handle a bat with bare hands.
At least seven species of bats roost in crevices under some bridges in Arizona.
- Contact your local Arizona Game and Fish Department office or e-mail the Bat Project email@example.com for advice before maintaining or removing a bridge.
Remember, removal is usually a last resort:
are protected by state law, and disturbing a colony of bats where
babies are present can result in dead bats and large fines. Bats
reproduce slowly compared to other small mammals, and their benefits
usually outweigh any harm they might cause. Bats should never be allowed
to remain inside human living areas, but bats outside can be tolerated
and even encouraged.
To prevent further problems:
- Remove bug lights and water sources, and turn off outside lights at night to avoid attracting bats.
- Bat-proof your home – This is the safest, most permanent way of keeping out unwanted bats:
- Consider allowing the bats to remain if they are not inside the living quarters of the house or causing property damage.
- Never exclude bats during the summer months (May
to September). This is the maternity period, when bats leave their
young in the roost to forage for food, and young bats could be trapped
inside and separated from their mothers.
- Find entry and exit points.
- If you cannot see
into the opening to determine whether all bats are gone, then hang
lightweight wire screening or hardware cloth over the entry and exit
holes, attaching it on the top and sides, but leave the bottom loose and
open. Bats inside can crawl out, but will not be able to re-enter.
- Wait a few days (or
weeksduring winter when bats are less active) to allow all of the bats
to leave. Then, permanently cover the entry hole with lightweight wire
screening, metal sheeting or hardware cloth.
- When all animals are
gone, and well after darkness has fallen, patch up entryways (remember,
bats can squeeze though openings as small as 3/8 inch).
- For help or advice with excluding bats from your house or property, please contact awildlife control business.
one or more bat houses on your property as an alternative for bats
roosting in your buildings. Plans are available online at batcon.org, or check with your local Arizona Game and Fish Department office to see if free bat houses are available. You can even monitor your bat house (click
the link for "Research Data Form”) to help the department learn the
best techniques for making bat houses most effective in Arizona.
Possible Health Concerns:
- Rabies - Bats are one of the known rabies vector
species in Arizona, although less than 1 percent of wild bats are
likely to have rabies at any given time. Symptoms of a rabid bat include
inability to fly, flying during daylight, lethargy and paralysis. Most
bats, even if sick, will not attack a person, but bats may bite if
handled. If a live bat is on or near the ground, then leave it alone,
keep pets and children away, and contact the local county health or
animal control agency. Anyone bitten by a bat should immediately seek
medical attention. If possible, the bat responsible for the bite should
be captured and tested for rabies.
– This disease is caused by a fungus (Histoplasma capsulatum) that
lives in soil enriched by bird or bat droppings. The fungus is rare in
dry Western climates, although it has been found in Arizona. It could be
present in dry, hot attics of buildings. Infection is caused by
inhalation of airborne spores in dust enriched by animal droppings. The
vast majority of histoplasmosis cases in humans is asymptomatic or
results in only flu-like symptoms, though a few individuals may become
seriously ill, especially if exposed to large quantities of spore-laden
dust. The disease can be avoided by not breathing dust suspected of
being enriched by animal feces. (Text from Bat Conservation
International Web site.)
Laws and Policies
- All bats in Arizona are protected and cannot be collected or killed. Proper exclusions may be performed where necessary.
- It is unlawful to use pesticides or other chemicals directly on bats.
- Bat exclusions should be done only with the advice of the Arizona Game and Fish Department or a wildlife control business,
and should not be attempted during the maternity season (generally May
through September) to avoid separating mothers from their young.