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Field Guide to Maryland Bats
Maryland has ten species of bats that lead varied lives. Some reside in Maryland all year long, and some migrate through Maryland in the spring and fall. Some species of bats live in groups called colonies and others live by themselves or in small families.
Bats belong to the order Chiroptera, which means “hand-wing.” Their hand is literally their wing and they are the only mammals that can fly.
Bats are more closely related to people than to mice and like humans, have hair, and feed their young milk.
Click on a picture or species name for profiles of each species or use the Maryland Bat Identification Dichotomous Key found below to identify Maryland bats.
See the online
Guide to Bat Anatomy
How do scientists tell one type of bat species from another?
Biologists use a dichotomous key to identify both plants and animals. Such keys include minute details about shapes and sizes of the parts of organisms that are being keyed out. Most bats that are found in the Maryland are not difficult to sort and identify into
basic types.
To identify a specific Maryland bat, it is necessary to recognize the features that distinguish one species from another. Before you can give a bat a name, you must first sort features of the organism into groups of similar and dissimilar types.
Once you are able to assign a name to a bat, you can begin to see the variation among the different species and distinguish one from another. Learning to use a Dichotomous Key is the first step in understanding the diversity of life. Following the dichotomous key for bat identification step-by-step, compare features of the bat you have chosen with the descriptions given, narrowing your choices until you determine identification.
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Maryland Bat Identification
Dichotomous Key |
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Dichotomous means having two equal parts. A key is a tool used to identify organisms.
A dichotomous key will give you a series of choices between two related characteristics.
Choices based on these two characteristics that best fit the organism in question will take you on
different paths to ultimately find the name of the organism. Choices typically begin with broad characteristics and become narrower as more choices are
required. Begin with number 1 (a). |
| 1(a). |
If dorsal (upper) surface of tail membrane furred |
Go to 2 |
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1(b). |
If dorsal (upper) surface of tail membrane naked or sparsely furred |
Go to 4 |
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2 (a).
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If fur black, many hairs silver-tipped |
Silver-haired Bat
(Lasionycteris noctivagans) |
| 2(b). |
If fur never uniformly black, hairs silver-tipped or not |
Go to 3 |
| 3(a). |
If ears conspicuously black edged with patches of yellowish hair scattered inside; fur yellowish to dark brown, distinctly frosted; tan throat patch |
Hoary Bat
(Lasiuruscinereus) |
| 3(b). |
If ears not conspicuously black-edged and bare; fur red-orange (male) or yellowish-brown (female), tips of hairs often frosted |
Eastern Red Bat
(Lasiurus borealis) |
| 4(a). |
If bats with brown fur only |
Go to 5 |
| 4(b). |
If small bat with yellowish fur and black wings; forearms 31-35mm; fur with three color bands, darkest band/base, lightest band/middle and darker tips |
Eastern Pipistrelle Bat
(Pipistrellus subflavus) |
| 5(a). |
If muzzle naked and black, tragus rounded |
Go to 6 |
| 5(b). |
If muzzle furred; tragus pointed (Genus Myotis) |
Go to 7 |
| 6(a). |
If large bat. Forearm more than 40mm |
Big Brown Bat
(Eptesicus fuscus)
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| 6(b). |
If small bat. Forearm less than 40mm |
Evening Bat
(Nycticeius humeralis) |
| 7(a). |
If ears more than 16mm; when laid forward, ears extend 2mm past end of nose
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Northern Long-eared Bat
(Myotis septentrionalis) |
| 7 (b). |
If ears less than 16mm |
Go to 8 |
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| 8(a). |
If calcar keeled
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Go to 9 |
| 8(b). |
If calcar not keeled |
Go to 10 |
| 9(a). |
If foot is greater than 8.5mm long; forearm usually greater than 35mm long; hair on toes short and sparse, nose pinkish, no black face mask |
Indiana Bat
(Myotis sodalis) |
| 9(b). |
If foot is less than 8.5mm long; forearm usually less than 35mm long; light colored fur with black face mask and lips |
Small-footed Bat
(Myotis leibii)
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| l0(a). |
If a few long hairs extend to tips of claws on foot or beyond
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Go to 11 |
| l0(b). |
If no long hairs extend to tips of claws on foot |
Indiana Bat
(Myotis sodalis) |
| 11. |
If fur glossy with sheen; not dense and woolly |
Little Brown Bat
(Myotis lucifugus) |
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