Habitat
Common vampire bats live in subtropical
and tropical regions, and inhabit humid tropical forests to arid
desert habitats. They live at elevations of up to about 7,500 feet
(2,288 m). These bats roost in secluded, nearly dark areas such as
caves with fissures, tree hollows, abandoned wells and buildings,
and deep mine shafts. |
Physical
Characteristics
Females are a bit larger than males, but otherwise both sexes are
nearly identical in appearance. Brown, gray, or brownish-red fur
covers their body; it is lighter on the underside. They have large
eyes, large pointed ears and no tail. Their nose appears compressed
and has two large nostrils. Their sense of smell is acute. The mouth
has very sharp canine and incisor teeth.
Common
vampire bats weight between 0.5-1.8 ounces (14-51 g). Average
head and body length is approximately 2.7-3.5 inches (7-9 cm),
the size of an adult human’s thumb. Wing
span averages 8 inches (20.3 cm). The thumb on each wing is well
developed. Unlike most bats, the legs of the common vampire bat
are very strong, enabling this bat to easily crawl, hop and jump. |
Life
Span
Life span in the wild is up to 9 years; in captivity
about 20 years |
Diet
In the wild: The
common vampire bat feeds on the blood of mammals, and sometimes
domesticated birds. Host animals might be cattle, horses
or pigs. Wild animals are also a valuable blood source, and
humans have sporadically supplied a tasty blood meal.
At the zoo: Cow blood |
If you
like this animal and find it particularly fascinating you
can adopt it!
Reproduction
Common vampire bats sexually mature at about 9 months of age, and mate
throughout the year. When the male finds a receptive female, he
climbs upon her back. Then he holds her wings with his, and grabs
the back of her neck with his mouth. Gestation lasts about 7 months,
after which a single young is born; twins occasionally occur. The
mother suckles her young for the first month, after which the young
also receives regurgitated blood meals from the mother. Young develop
quickly, accompanying their mother on hunts by 4 months of age.
Young are fully grown by 5 months and are fully weaned by 10 months
of age.
Life Cycle
Common vampire bats are social animals. They roost alone,
in small groups, or in colonies of up to 2,000 bats. When colonies
are larger than about 50 bats, they split up into smaller groups consisting
of females and their young. A single male often roosts close to each
female group and attempts to maintain his right to breed with the females
of the group. Clashes between males frequently occur; they are hard-fought
battles that involve biting, kicking and battering with wings.
Social Bonds are enhanced by grooming, this normally
occurs between females and young, and female to female. A female
grooms another female for several minutes, after which the recipient
regurgitates part of their blood meal for the other to consume. This
practice proves important since one in three bats are unsuccessful
in finding a blood meal each night. A vampire bat dies if it does
not get a blood meal in two to three days. One strategy for survival
is to groom or beg from another bat, in order to receive a much needed
blood meal.
Dinner on the Hoof
Flying about 3 feet (0.9 m) off the ground, the bat’s sharp sense
of smell and echolocation find a “victim”. Echolocation
happens when the bat sends ultra-high frequency sounds through its
nose. The sounds reflect off objects in their surroundings, bouncing
back to the bat’s sensitive ears. The bat determines the distance
to its target by how long it takes the sounds to return. This bat is
lucky—there’s a sleeping cow right ahead!
So as not to alert the cow, the bat lands on the ground and easily
crawls or hops to its snoozing dinner using their thumbs, forearms
and wings. It lightly climbs onto the cow and uses heat sensors in
its nose to find where blood is near the skin’s surface. The bat licks the site clean with its tongue
and then trims the cow’s hair with its teeth. It then painlessly cuts
through the skin and injects saliva containing a chemical to prevent blood
clots. The bat then laps oozing blood with its tongue. The bat soon becomes
engorged with blood and is too heavy to fly away. It crawls off the cow and
moves along the ground to a safe place while digestion lightens its heavy load.
|
Fascinating
Facts
- Draculin, a blood-thinning drug developed
from vampire bat saliva, helps prevent strokes and heart
attacks in humans!
- The common vampire bat is the only bat that
can take off vertically!
- Common
vampire bats avoid attacking dogs because canines can detect
a bat’s
high-frequency sounds as they approach!
|

Vampire
bats are in the Night Exhibit. After the zoo closes, the light in
this exhibit is gradually brought up to an artificial “day” lasting between 10-14 hours. During
this “day” the nocturnal vampire bats sleep. They become
active during the zoo visitor’s day as their “night” begins.
The lights are gradually dimmed to simulate dusk, then darkness.

Vampire bat populations are healthy throughout their
range. In many Latin countries, however, government-sponsored programs
attempt to eradicate vampire bats. Over the last several decades,
cattle ranches spread throughout Mexico, Central and South America.
Vampire bat populations soared and their range expanded, as cattle
are easy targets. Unfortunately, vampire bats can transmit rabies
and other diseases to cattle. Annually, over 100,000 cattle die from
the bites of vampire bats, and ranchers lose millions of dollars
in revenue. During these eradication programs, people kill other
harmless bat species mistaken for vampire bats. Additionally, many
species of bats are in trouble due to destruction of their habitat
and roosting sites.
All bats have an enormous ecological significance. Insect-eating
bats consume huge quantities of flying insects — a single bat
may consume 500 mosquitoes in an hour. Nectar-feeding bats are important
pollinators. Fruit-eating bats disperse seeds over great distances
in tropical forests, ensuring food supplies for other forest inhabitants.
How You Can Help!
The effort to save bats and other animals requires cooperation and
support at the regional, national and international levels. You
can help in this cause. Join and become active in a conservation
organization of your choice. Tell your elected representatives
on the national, state and local levels about the importance of
preserving wild habitats and endangered species.
Contact Woodland Park Zoo at webkeeper@zoo.org about supporting conservation
programs at the zoo. Learn other ways you can help conserve wildlife
and habitats by visiting our How You Can Help page.
Sources and Suggested Reading
Nowak, Ronald M. 1994. Walker’s Bats of the World. The
Johns Hopkins University Press, Baltimore, MD. 287 p.
For Kids!
Horowitz, Ruth. 1991. Bat Time. Four Winds Press,
New York, NY.
Milton, Joyce. 1994. Bats and Other Animals of the Night. Random House,
New York, NY. 32 p.
* Taxonomic classification varies between
references. Classification information used in this fact sheet was
taken from Mammal Species of the World: A Taxonomic and Geographic
Reference; Don E. Wilson and DeeAnn M. Reeder, Second Edition, 1993. |