FIELD IDENTIFICATION OF TERRESTRIAL SMALL MAMMALS
FROM THE TULAROSA VALLEY, NEW MEXICO
Prepared by:
Jennifer K. Frey, Ph.D.
Department of Biology and Museum of Southwestern Biology
University of New Mexico
Albuquerque, New Mexico 87131
24 June 1996
(please send corrections/comments to [email protected])
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ORDER INSECTIVORA
Family Soricidae
I.
'pointed' nose; small eyes and ears; total length < 95; tail about 1/2 total length
Notiosorex crawfordi
desert shrew
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ORDER LAGOMORPHA
Family Leporidae
I.
II.
Large area of black on end of back side of ears; black stripe down rump and
top of tail
No large area of black on end of back side of ears; no black stripe down rump and
top of tail
Lepus californicus
black-tailed jack rabbit
Sylvilagus audubonii
desert cottontail
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J.K. Frey--Small mammals of the Tularosa Valley
2
ORDER RODENTIA
Family Sciuridae
Cynomys ludovicianus
black-tailed prairie dog
I.
Large size; tail < 1/3 total length; tan
II.
Small size; tail > 1/3 total length
A.
Sides of head striped; distinct stripes on back; Carrizozo Malpais only
B.
Tamias canipes
gray-footed chipmunk
Sides of head not striped
1.
Back with 2 white stripes; tail white ventrally;
Carrizozo Malpais only
Ammospermophilus interpres
Texas antelope squirrel
2.
Back tan with numerous white spots; tail about 1/2 body length Spermophilus spilosoma
spotted ground squirrel
3.
Grayish/blackish; back mottled; bushy tail; tail about equals
Spermophilus variegatus
body length; Carrizozo Malpais only
rock squirrel
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Family Geomyidae
I.
Cheek pouches; small eyes and ears; neck not constricted; tail < 1/3 total length
A.
Two grooves on each upper incisor; total length usually < 250
B.
One groove on each upper incisor; total length usually > 250
Geomys arenarius
desert pocket gopher
Cratogeomys castanops
yellow faced pocket gopher
(formerly Pappogeomys castanops)
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Family Heteromyidae
*All with cheek pouches
I.
Tail terete (hair at end of tail equal in length to base)
A.
Total length < 120 mm; tail < 55; large whitish patch behind ears;
conspicuous molt lines; many black hairs
B.
Perognathus flavus
silky pocket mouse
Total length > 120; tail > 55
1.
2.
Total length 120 - 140; no distinct white patch behind ears;
color uniform; no conspicuous molt lines; few black hairs
Total length > 170; orangish stripe on sides
Perognathus flavescens apache
Apache pocket mouse
Chaetodipus hispidus
hispid pocket mouse
(formerly genus Perognathus)
J.K. Frey--Small mammals of the Tularosa Valley
II.
3
Tail tufted
A.
Pocket Mice
1.
long stiff hairs on rump, buffy venter; prefers rocky habitats
2.
B.
rump hairs all same length, venter not buffy
Kangaroo Rats
1.
White-tipped tail, large size, 4 hind toes
2.
Black-tipped tail, medium size
a.
5 hind toes
b.
Chaetodipus intermedius
rock pocket mouse
Chaetodipus penicillatus
Desert pocket mouse
Dipodomys spectabilis
banner-tailed kangaroo rat
Dipodomys ordii
Ord's kangaroo rat
Dipodomys merriami
Merriam's kangaroo rat
4 hind toes
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Family Muridae
WOODRATS
I.
Ears prominent and naked; body and tail sharply bicolored
A.
Dorsal color grey; prefers grasslands
B.
Dorsal color brown
1.
Throat hairs with white bases; Carrizozo Malpais population
is black
2.
Throat hairs with dark bases; Carrizozo Malpais population
is dark
Neotoma micropus
southern plains woodrat
Neotoma albigula
white-throated woodrat
Neotoma mexicana
Mexican woodrat
COTTON RAT
I.
Ears partly hidden in fur and haired; body and tail not sharply bicolored;
prefers grasslands
Sigmodon hispidus
hispid cotton rat
J.K. Frey--Small mammals of the Tularosa Valley
4
MICE
I.
Upper incisors with groove
A.
Tail < 1/2 total length; tail with narrow distinct dorsal stripe
B.
II.
Tail > 1/2 total length; tail darker above than below but without
distinct stripe
Upper incisors without groove
A.
Belly tan
1.
tail about same length as body; tail > 60; tail nearly naked, scaly;
nearly uniformly colored
B.
Belly white
1.
Tail tufted
a.
Ear > hindfoot; ear > 23; tail sharply bicolored;
tail < 1/2 total length
b.
Ear < hindfoot; ear < 23
2.
Ear < 20; hindfoot < 23; ear < hindfoot
3.
2.
Ear > 20; hindfoot > 23; ear > hindfoot;
tail > 1/2 total length; black on Carrizozo
Malpais
Tail not tufted; distinctive sharp odor
a.
Tail < 60% body; tail with white tip
1.
Tail < half length of head and body
2.
b.
Tail > half length of head and body
Tail > 60% body
1) tail < body
a) hindfoot < 22 mm; tail sharply
bicolored
b) hindfoot > 22 mm; tail not sharply
bicolored but darker above
2)
Tail > body, tail almost naked;
orangish color on sides
Reithrodontomys montanus
plains harvest mouse
Reithrodontomys megalotis
western harvest mouse
Mus musculus
house mouse
Peromyscus truei
piñon mouse
Peromyscus boylii
brush mouse
Peromyscus nasutus
rock mouse
(formerly Peromyscus difficilis)
Onychomys leucogaster
northern grasshopper mouse
Onychomys arenicola
Mearns' grasshopper mouse
Peromyscus maniculatus
deer mouse
Peromyscus leucopus
white-footed mouse
Peromyscus eremicus
cactus mouse