Animal Info - Gray Bat
(Other Names: Gray Myotis, Howell's Bat)
1. Profile (Picture)
3. Status and Trends (IUCN Status, Countries Where
Currently Found, Population Estimates, History of Distribution, Threats and Reasons
4. Data on Biology and Ecology (Weight, Habitat, Birth Season, Early
Development, Diet, Social Organization)
Bat #1 (92 Kb JPEG) (Smith.
Inst. N. Amer. Mamm.); Gray
Bat #2 (85 Kb JPEG) (Smith.
Inst. N. Amer. Mamm.)
The gray bat weighs 7 - 9 g (0.2 - 0.3 oz). Its limestone roosting caves and foraging
areas are near water bodies such as streams, ponds and reservoirs. Its diet consists
predominantly of insects. All species of the genus Myotis, including the
gray bat, roost by day and forage at night. The feeding flights usually alternate with periods of
rest, during which the bats hang to digest their catch. Colonies of the gray bat travel up
to 6.6 km (4.1 mi) from roost to foraging areas. During the summer a colony occupies a
definite home range and may move among 6 or more
roosting caves. Large-scale movement to hibernation sites begins in September and covers
17 - 437 km (11 - 271 mi) (Nowak & Paradiso
Gray bats are highly gregarious. They
hibernate in large colonies in caves during the winter. In the summer, females gather in
smaller colonies at other caves to give birth, while the males collect nearby After late
July, the males join the maternity colonies.
The gray bat occurs in the central USA. It is
thought to have declined mainly due to destruction by vandals and disturbance by spelunkers and tourists.
*** Individual gray bats almost invariably return to the same caves in which they
hibernate over winter and roost in summer (Altringham
*** The gray bat occupies the coldest reported summer roosts in North America (down to
13 deg C (55 deg F)).
Status and Trends
- 1970's - 1994: Endangered
- 1996 - 2004: Endangered (Criteria: A1c) (Population Trend: Decreasing)
Countries Where the Gray Bat Is Currently Found:
2004: Occurs in the USA (IUCN
[Note: Figures given are for wild populations only.]
- WORLD (USA)
- 1976: More than 2 million (about 90% of all gray bats east of the Mississippi River and
south of Kentucky were thought to hibernate in 3 caves with populations of 125,000,
250,000 and 1,500,000) (Nowak & Paradiso 1983)
History of Distribution:
The gray bat is found in the USA from eastern
Kansas and Oklahoma to western Virginia south to northwestern Florida. As of 1987,
approximately 95% of the population was estimated to hibernate in nine roosts, with one
containing more than 50% of the population (Burton
& Pearson 1987).
Map #1 (17 Kb) (NatureServe
Distribution Map #2 (53 Kb) (Bat Cons. Intl.)
Threats and Reasons for Decline:
As of 1987 the gray bat was estimated to have declined by up to 76% from its original
population (Burton & Pearson 1987).
The decline has been attributed mainly to destruction by vandals and disturbance by spelunkers and tourists. Its distribution has always
been patchy, but it is becoming increasingly fragmented.
Data on Biology and Ecology
The gray bat weighs 7 - 9 g (0.2 - 0.3 oz)
The gray bat roosts in limestone caves. It
roosts near and forages over water bodies
such as streams, ponds and reservoirs.
Young are born in the summer. Births are highly synchronous.
A young gray bat makes its first flight anywhere from 24 - 33 days after birth,
depending on the size and temperature of its birth colony.
The gray bat's diet consists predominantly of insects.
Gray bats are highly gregarious,
concentrating in large numbers in a small number of caves. They hibernate in large
colonies in caves during the winter. In the summer, females gather in smaller colonies at
other caves to give birth, while the males collect nearby. After late July, the males join
the maternity colonies.
Altringham 1996, Bat
Cons. Intl., Burton & Pearson 1987, IUCN 1994, IUCN 1996,
IUCN 2000, IUCN
2004, NatureServe Expl., Nowak
& Paradiso 1983, Smith.
Inst. N. Amer. Mamm., Stebbings 1980
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Last modified: May 17, 2006;