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HomeSkulls

Dental Formulae of Mammal Skulls
of  North America

 

How to use this chart

  

This chart is useful for identifying skulls when there are still teeth present.

Count the number of teeth of each type in the upper (U) and lower (L) jaw.  Each row in the chart shows the number of each type of teeth in the Upper (U) and Lower (L) jaw, and on the right and left side.  The numbers are of the form "5-5" (for example).   This means that there are 5 teeth on the left side, and 5 teeth on the right side.

For example, the Opossum has 5 incisors on the left upper jaw, 5 incisors on the right upper jaw, 4 incisors on the left lower jaw, and 4 incisors on the right lower jaw.

If you can't tell the different types of teeth apart, start by getting the total number of teeth in both upper and lower jaws.  Then use the "Total" column as a starting point.   From there you may be able to narrow it down by the size of the skull (a raccoon skull will be smaller than a bear skull, for example), or by other characteristics.

The chart is arranged in order by the total number of teeth, from the most down to the least number.

Incisors are the teeth closest to the front of the skull, Molars are the farthest to the rear.

Sometimes there are multiple species listed in the Latin Names and Common Names columns.  This means that all of the species listed have that particular dental formula.

Sometimes a species will have a varying number of teeth.  This is indicated, for example, as follows:
Rangifer (32/34) (which means that they will have either 32 or 34 teeth in total),
or Dasypus (28-32) which means that they will have between 28 and 32 teeth in total.

  
  Incisors Canines Premolars

Molars

Total U
Total L

Total

Latin Names

Common Names
U
L

5-5
4-4

1-1
1-1

3-3
3-3

4-4
4-4

26
24

50

Didelphis Opossum
U
L

3-3
3-3

1-1
1-1

4-4
4-4

3-3
3-3

22
22

44

Condylura
Parascalops
Scapanus
Sus
Starnose Mole
Hairytail Mole
Townsend, Pacific, California Mole
Wild Boar
U
L

3-3
3-3

1-1
1-1

4-4
4-4

2-2
3-3

20
22

42

Alopex
Canis
Thalarctos
Urocyon
Ursus
Vulpes
Arctic Fox
Coyote, Grey Wolf, Red Wolf
Polar Bear
Grey Fox
Black, Grizzly, Big Brown Bear
Red, Swift, Kit Fox
U
L

3-3
3-3

1-1
1-1

4-4
4-4

2-2
2-2

20
20

40

Bassariscus
Nasua
Procyon
Ringtail
Coati
Racoon
U
L

2-2
3-3

1-1
1-1

3-3
3-3

3-3
3-3

18
20

38

Myotis
Pecari
Myotis group of Bats
Peccary
U
L

3-3
3-3

1-1
1-1

4-4
4-4

1-1
2-2

18
20

38

Gulo
Martes
Wolverine
Marten, Fisher
U
L

3-3
2-2

1-1
0-0

3-3
3-3

3-3
3-3

20
16

36

Scalopus Eastern Mole
U
L

2-2
1-1

1-1
1-1

3-3
4-4

3-3
3-3

18
18

36

Neurotrichus Shrew-Mole
U
L

2-2
3-3

1-1
1-1

2-2
3-3

3-3
3-3

16
20

36

Lasionycteris
Plecotus
Silver-haired Bat
W. & E. Big-eared Bat
U
L

3-3
3-3

1-1
1-1

4-4
3-3

1-1
2-2

18
18

36

Lutra River Otter
U
L

2-2
2-2

1-1
1-1

2-2
3-3

3-3
3-3

16
18

34

Macrotus
Mormoops
Leafnose Bat
Leafchin Bat
U
L

2-2
3-3

1-1
1-1

2-2
2-2

3-3
3-3

16
18

34

Euderma
Pipistrellus
Spotted Bat
W. & E. Pipistrel
U
L

3-3
3-3

1-1
1-1

3-3
3-3

1-1
2-2

16
18

34

Mephitis
Mustela

Spilogale
Taxidea
Striped Skunk
Shorttail, Least, Longtail Weasels
Black-footed Ferret, Mink
Spotted Skunk
Badger
U
L

0-0
3-3

1-1
1-1

3-3
3-3

3-3
3-3

14
20

34

Cervus
Rangifer (32/34)
Elk
Woodland, Barren Ground Caribou
U
L

3-3
1-1

1-1
1-1

3-3
1-1

3-3
3-3

20
12

32

Blarina
Microsorex
Sorex
Shorttail Shrew
Pigmy Shrew
Various Shrews
U
L

2-2
3-3

1-1
1-1

1-1
2-2

3-3
3-3

14
18

32

Eptesicus Big Brown Bat
U
L

1-1
3-3

1-1
1-1

2-2
2-2

3-3
3-3

14
18

32

Lasiurus borealis
Lasiurus cinereus
Lasiurus seminolus
Tadarida brasiliensis
Red Bat
Hoary Bat
Seminole Bat
Mexican Freetail Bat
U
L

3-3
2-2

1-1
1-1

3-3
3-3

1-1
2-2

16
16

32

Enhydra Sea Otter
U
L

3-3
3-3

1-1
1-1

2-2
3-3

1-1
2-2

14
18

32

Conepatus Hognose Skunk
U
L

0-0
3-3

0-0
1-1

3-3
3-3

3-3
3-3

12
20

32

Alces
Antilocapra
Bison
Odocoileus
Oreamnos
Ovibos
Ovis
Rangifer (32/34)
Moose
Pronghorn
Bison
Mule, Whitetail Deer
Mountain Goat
Muskox
Bighorn, White Sheep
Woodland, Barren Ground Caribou
U
L

0-0
0-0

0-0
0-0

8-8
8-8

16
16

32

Dasypus (28-32) Armadillo (28-32 teeth)
U
L

3-3
1-1

1-1
1-1

2-2
1-1

3-3
3-3

18
12

30

Cryptotis Least Shrew
U
L

2-2
0-0

1-1
1-1

2-2
3-3

3-3
3-3

16
14

30

Choeronycteris Hognose Bat
U
L

2-2
2-2

1-1
1-1

2-2
3-3

2-2
2-2

14
16

30

Leptonycteris Longnose Bat
U
L

1-1
3-3

1-1
1-1

1-1
2-2

3-3
3-3

12
18

30

Lasiurus ega
Lasiurus intermedius
Nycticeius
Western Yellow Bat
Eastern Yellow Bat
Evening Bat
U
L

1-1
2-2

1-1
1-1

2-2
2-2

3-3
3-3

14
16

30

Eumops
Tadarida femorosacca
Tadarida molossa
Mastiff Bats
Pocketed Freetail Bat
Big Freetail Bat
U
L

3-3
3-3

1-1
1-1

3-3
2-2

1-1
1-1

16
14

30

Felis Jaguar, Mountain Lion, Ocelot
U
L

3-3
1-1

1-1
1-1

1-1
1-1

3-3
3-3

16
12

28

Notiosorex Grey Shrew
U
L

1-1
2-2

1-1
1-1

1-1
2-2

3-3
3-3

12
16

28

Antrozous Pallid Bat
U
L

3-3
3-3

1-1
1-1

2-2
2-2

1-1
1-1

14
14

28

Lynx Lynx
Bobcat
U
L

2-2
1-1

0-0
0-0

3-3
2-2

3-3
3-3

16
12

28

Lepus
Sylvilagus
Hares & Jackrabbits
Rabbits
U
L

0-0
0-0

0-0
0-0

7-7
7-7

14
14

28

Dasypus (28-32) Armadillo (28-32 teeth)
U
L

2-2
1-1

0-0
0-0

3-3
2-2

2-2
3-3

14
12

26

Ochotona Pikas
U
L

1-1
1-1

0-0
0-0

2-2
1-1

3-3
3-3

12
10

22

Ammospermophilus
Aplodontia
Citellus
Cynomys
Eutamias
Glaucomys
Marmota
Sciurus aberti
Sciurus carolinensis
Sciurus griseus
Tamiasciurus
Antelope Squirrels
Mountain Beaver
Rock, Ground, Golden-mantled Squirrels
Prairie Dogs
Chipmunks except Eastern
Flying Squirrels
Woodchuck, Marmots
Tassel-Eared Squirrel
Eastern Grey Squirrel
Western Grey Squirrel
Red Squirrel (usually 20 teeth)
U
L

1-1
1-1

0-0
0-0

1-1
1-1

3-3
3-3

10
10

20

Castor
Cratogeomys
Dipodomys
Erethizon
Geomys
Liomys
Microdipodops
Myocastor
Perognathus
Sciurus apache
Sciurus arizonensis
Sciurus niger
Tamias
Tamiasciurus
Thomomys
Beaver
Mexican Pocket Gopher
Kangaroo Rats
Porcupine
Pocket Gophers (except Mexican)
Mexican Pocket Mouse
Dark, Pale Kangaroo Mouse
Nutria
Pocket Mice (except Mexican)
Apache Fox Squirrel
Arizona Grey Squirrel
Eastern Fox Squirrel
Eastern Chipmunk
Red Squirrel (also 22), Chickaree
Pocket Gophers
U
L

1-1
1-1

0-0
0-0

1-1
0-0

3-3
3-3

10
8

18

Zapus Jumping Mice (except Woodland)
U
L

1-1
1-1

0-0
0-0

0-0
0-0

3-3
3-3

8
8

16

Baiomys
Clethrionomys
Dicrostonyx
Lagurus
Lemmus
Microtus
Mus
Napaeozapus
Neofiber
Neotama
Ondatra
Onychomys
Oryzomys
Peromyscus




Phenacomys
Pitymys
Rattus
Reithrodontomys
Sigmodon
Synaptomys
Pygmy Mouse
Redback Voles
Collared Lemmings
Sagebrush Vole
Brown Lemming
Voles (except Pine & Sagebrush)
House Mouse
Woodland Jumping Mouse
Florida Water Rat
Woodrats
Muskrat
Grasshopper Mice
Rice Rat
Mice: Cactus, Merriam, California,
Canyon, Deer, Sitka, Oldfield,
White-footed, Cotton, Brush,
White-ankled, Pinon, Rock, Florida, Golden
Phenacomys
Pine Vole
Norway, Black Rats
Harvest Mice
Cotton Rats
Bog Lemmings

For more information, see DeLoy Roberts Skull Collection