Mammals of Indiana: A Field Guide

Identification Keys

31 Identification Keys KEY TO ORDERS OF MAMMALS OF INDIANA USING SKINS OR WHOLE ANIMALS 1. Front limbs modified as wings (Fig. 1); thin interfemoral membrane (uropatagium) connecting hind limbs and tail.....................................Bats, Order Chiroptera, p. 89 No wings; uropatagium absent or not as described above.........................................................................................2 2. Toes terminating in hooves . . . Hoofed Mammals, Order Artiodactyla...................................White-tailed Deer (Odocoileus virginianus), p. 281 Toes terminating in claws......................................................3 3. With well-developed armor of bony plates over much of the body. ......................................Nine-banded Armadillo (Dasypus novemcinctus), Order Cingulata, p. 129 Animal not covered with armored plates...........................4 4. Innermost toe of hind foot thumblike and without claw; female with abdominal pouch; ears thin and naked; tail round, naked, black at base, whitish on terminal half or more; fur grayish..............Virginia Opossum (Didelphis virginiana), Order Didelphimorphia, p. 59 Not as above.............................................................................5 5. Always five clawed toes on front foot (first toe sometimes reduced, high on inside of foot, and not touching ground when animal walks)................................................................6 Usually only four well-clawed toes on front foot (thumb may be present as small knob with nail); if five, then tail either naked and much flattened (laterally or dorsoventrally ) or a short cottony tuft.................................................7 6. Length of head and body less than 115 mm, or if more than 115 (in some moles) no ears visible and belly not white.......... Shrews and Moles, Order Soricomorpha, p. 63 Length of head and body more than 115 mm, ears visible..........................Carnivores, Order Carnivora, p. 233 Mammals.indb 31 3/31/10 3:08 PM 32   Naming and Identifying Mammals 7. Ear longer than tail; hind foot with four claws covered with fur; soles of feet completely covered with dense fur; tail forming a cottony tuft.........................................Rabbits, Order Lagomorpha, p. 133 8. Ear shorter than tail; hind foot with five well-clawed toes; soles of feet not completely covered with dense fur; tail not a cottony tuft........Rodents, Order Rodentia, p. 143 KEY TO SPECIES OF ORDER SORICOMORPHA 1. Forefeet greatly developed for burrowing, more than twice as wide as hind feet and turned outward; eyes not visible . . . Moles. ...............................................................2 Forefeet less than twice as wide as hind feet and not turned outward; eyes small but visible . . . Shrews............3 2. Tail more than 60 mm; 22 fleshy tentacles on snout........... . .........................Star-nosed Mole (Condylura cristata), p. 86 Tail short, generally not more than 45 mm; snout lacking tentacles...............Eastern Mole (Scalopus aquaticus), p. 82 3. Tail generally less than 28 mm and about 20 percent or less of the total length. ............................................................4 Tail generally 27 mm or more and about 30–40 percent of the total length . . . Sorex...................................................5 4. Color gray; total length 95 mm or more. ............................... . ....................Short-tailed Shrew (Blarina brevicauda), p. 76 Color brownish; total length less than 95 mm..................... . ...................................... Least Shrew (Cryptotis parva), p. 80 5. Shrews brownish, total length 85–100 mm, weight about 3–5 grams.................................................................................6 Shrews often grayer and either smaller (usually 2–3 grams) or larger (usually over 5 grams)...............................7 6. Tail shorter, about 32–38 percent of total length; longest hairs at end of tail when unworn about 2–3 mm................. . ..................... Southeastern Shrew (Sorex longirostris), p. 73 Tail longer, about 35–46 percent of total length; longest hairs at end of tail when unworn about 4.5–6 mm. ............. . ....................................Masked Shrew (Sorex cinereus), p. 64 7. Shrews tiny. Total length under 90 mm; weight seldom much over 3 grams. This shrew is very similar to Sorex Mammals.indb 32 3/31/10 3:08 PM Identification Keys   33 cinereus and S. longirostris but is smaller. (The best character for separating this species from those two is in the unicuspid teeth, which can be seen by pulling back the upper lip. Unicuspids 3 and 5 are reduced giving the appearance of 3 unicuspid teeth in this species. There are four semi-equal in size with the fifth smaller but clearly visible in Sorex cinereus and S. longirostris.)........................ . ............................................ Pygmy Shrew (Sorex hoyi), p. 70 Shrews larger (5–9 grams), and usually over 100 mm total length............................Smoky Shrew (Sorex fumeus), p. 68 KEY TO SPECIES OF ORDER CHIROPTERA 1. Interfemoral membrane with hairs above, either completely or on basal half...........................................................2 Interfemoral membrane without hairs above. ....................4 2. Interfemoral membrane with hairs on basal half; body color dark chocolate or blackish, with few silvery tipped hairs dorsally............................................... Silver-haired Bat (Lasionycteris noctivagans), p. 110 Interfemoral...