ILLUSTRATED CHECKLISTS OF ANIMALS
provided are specific to the geographical scope of
this paper. Descriptions of mammals are limited to
adults. Characters given are primarily those which
are outstanding and distinguish 1) orders, families,
or major groups within a family, 2) one species from
other similar species, and 3) males from females of
a species. Primarily two measurements are provided:
HB) the length of the head and body from the
tip of the nose to the base of the tail and T)
the length of the tail. The height at the shoulder
is noted where customary. Approximate weights are
given for the larger animals. Some details of the
natural history are provided as identification aids.
arrangement of this information is as follows: order
(common names within order), characters common to
the order (or major group within the order), common
names of individual species (scientific name, family
name), size, description, and habitat. Descriptions
mostly follow The Audubon Society Field Guide to
North American Mammals.
to each written description is a graphic illustration
taken with permission from California Department of
Fish and Game's California's Wildlife.
(Marsupials or pouched mammals)
females have no placenta, rather a pouch in which
newborn embryos and older juveniles are nourished
Virginia opossum (Didelphis virginiana,
Didelphidae) HB 15 to 20 inches; T 10 to 21
inches. The opossum is approximately the size
of a house cat. The fur on its back is grizzled
white and may appear brown or blackish. Its
belly has black-tipped fur covered with white
hairs. Its long, naked, prehensile tail is conspicuous.
The opossum is active yearlong. It is nocturnal
(active from dusk through dawn). It inhabits
moist woodland and brushy habitats in riparian,
woodland, scrubland, and urban communities.
It is less common in grassland communities.
and moles have short, dense fur, small eyes,
and five clawed toes on their fore and hind feet.
Their small ears are usually hidden under their
fur. They eat a variety of invertebrates.
shrew, adorned shrew (Sorex ornatus,
Soricidae) HB 2 and 21/2 inches; T 11/4 to 13/4
inches. The ornate shrew's back is grayish-brown;
its belly lighter. The tail is dark brown above,
lighter below, and is darkest at the tip. The
ornate shrew is active year-round. It is crepuscular
and nocturnal. It inhabits woodland, chaparral,
grassland, and emergent riparian communities.
However it is not often seen.
mole (Scapanus latimanus, Talpidae)
HB 41/2 to 53/4 inches long; T 3/4 to 13/4 inches.
The broad-footed mole is brown-gray in color.
It has a short, hairy tail. It is active yearlong
both day and night, especially after rains.
It burrows just below the surface, pushing the
surface slightly upward. It inhabits annual
grassland, pastoral, and riparian communities.
have enlarged arm bones and muscles that resemble
wings. They are able to walk and climb as well
as fly. They may swing from branch to branch.
At rest, they hang upside down by their feet (sometimes
just one foot). Their eyes are small, and they
have poor vision. However, they have highly developed
echolocation, projecting through their noses and/or
mouths 30 to 60 squeaks per second at a frequency
of 30,000 to 100,000 cycles per second. This is
inaudible to humans. (The human voice has a much
lower frequency, between 300 and 3,000 cycles
per second.) Bats also utter shrill chirps and
screeches. Most mate in fall and undergo delayed
fertilization (births occur after the cold winter).
They live up to 20 years. They are insectivorous.
BATS have ear lobes that form a tragus: a
projection from the ear's inner base. Their tails
extend only a bit beyond the edge of the interfemoral
bat (Lasiurus cinereus, Vespertilionidae)
HB 2 to 31/2 inches; T 13/4 to 21/2 inches.
The hoary bat's back has fur that is light brown
and is tipped in white. Its throat is a buff
color. It hibernates. When active, it is nocturnal.
By day it hangs from the branches of evergreen
trees. It eats mostly moths. It inhabits woodland
communities, particularly open habitats and
bat (Antrozous pallidus, Vespertilionidae)
HB 3 inches; T 11/2.to 17//8 inches. The pallid
bat has big ears. It is cream-colored or beige
above and almost white below. It hibernates.
It is nocturnal. It eats a variety of insects,
as well as scorpions and lizards. It has a variety
of habitats, especially open, dry areas with
rocky places for roosting within grassland,
woodland, and scrubland communities.
BATS are snub-nosed and thick set. They have
naked tails which extend well beyond the edge
of the interfemoral membrane. At least half of
the tail is free. The thumb and toe claws have
double talons. The spoon-shaped bristles on the
hind toe of their feet are used in grooming.
free-tailed bat (Tadarida brasiliensis,
Molossidae) HB 2 to 23/4 inches; T 11/2 to 13/4
inches. This bat's fur is dark brown-gray above,
although the hairs are whitish at their base.
It can be active yearlong, but locally it hibernates.
It is nocturnal. It often forms huge colonies
in caves in the southwest. It occupies all habitats,
especially open areas in woodland, scrubland,
and grassland communities. It is very common.
(Rabbits and hares)
AND HARES have two pairs of upper incisors,
the larger pair in front of the more reduced pair.
As in rodents, these continue to grow throughout
the life of the animal, but are worn down by use.
Rabbits and hares have relatively long ears and
hind legs adapted for jumping. Their prominent
eyes bulge to the sides of their heads, providing
them with a wide field of vision and better protection
from predators. Their sense of smell is well developed.
They also sense vibrations in the ground and thump
with their hind legs to communicate with one another.
Another form of communication used is a piercing
call of distress. They are grazers.
rabbit (Sylvilagus bachmani, Leporidae)
HB 10 to 13 inches; T 3/4 to 13/4 inches. The
brush rabbit's fur is a reddish brown mottled
with black, lighter in winter. It has short
legs, a small tail, and short, dark ears. It
is active year-round. It is mainly crepuscular,
but may also be active day or night. It inhabits
dense, brushy areas of grassland, scrubland,
and coastal live oak woodland communities.
(Desert) cottontail (Sylvilagus audubonii,
Leporidae) HB 12 to 131/2 inches; T 13/4 to
3 inches. This rabbit is buff-brown above and
white below. It has moderately long ears. It
is active yearlong. It is primarily crepuscular,
but occasionally is active by day or night.
It uses small, scattered patches of dense scrub
for cover and patches of scrub edged with a
herbaceous cover for foraging. It occupies riparian
hare (jackrabbit) (Lepus californicus,
Leporidae) HB 16 to 20 inches; T 2 to 41/2 inches.
The black-tailed hare is buff-sandy-gray peppered
with black above and white below. It has very
long ears. The upper side of its tail has a
black stripe bordered in white which extends
onto the rump. It is active yearlong. It is
diurnal, and especially active in the late afternoon.
It inhabits herbaceous and dry, shrubby areas
in woodland, chaparral, and coastal scrub, particularly
where these communities are edged by grassland.
(Squirrels, rats, mice, and relatives)
are the most numerous and diverse group of mammals.
They have only two pairs of incisors, upper and
lower. They have no canines before the molars,
only a gap. As in rabbits and hares, the incisors
grow throughout the life of the rodent and are
kept from growing too large by gnawing. Rodents'
eyes bulge from the sides of their heads which
permits them to see in front of and behind them.
Most rodents have four toes on their fore feet
and five on the hind feet.
are primarily diurnal. Many hibernate, and some
ground squirrel (Spermophilus beecheyi,
Sciuridae) HB 8 to 11 inches; T 6 to 9 inches.
This squirrel is brownish with buff-colored
flecks. It has whitish areas along the sides
of the neck across the shoulders to the haunches
and a dark V-shaped pattern across the back
of the shoulders (with the 'V' pointing forward).
The bushy tail is brown-gray edged in white.
The California ground squirrel is active yearlong,
although it may become torpid when food is scarce
and/or temperatures are extreme, especially
in late summer. It is diurnal. It burrows in
the ground and creates a central entrance mound
from which radiate numerous pathways. It occupies
open and disturbed areas, being particularly
numerous in heavily grazed pastures.
gray squirrel (Sciurus griseus, Sciuridae)
HB 8 to 11 inches; T 91/2 to 12 inches. This
squirrel is gray with many white-tipped hairs
above. Its belly is white. The backs of its
ears are reddish brown. Its long, bushy tail
is banded in gray, white, and black. It is active
year-round. It is diurnal, active especially
in early morning and late afternoon/evening.
It nests in trees, making large, round, hollow
nests made of leaves. It inhabits riparian and
mature coastal live oak woodland communities.
GOPHERS are found only in North America. They
have stout bodies, short necks, short fur, small
ears and eyes, a naked (or nearly naked) tail,
and large, external fur-lined cheek pouches. Their
lips close behind their incisors, so no dirt gets
in their mouths while digging. They spend almost
all the time underground in their burrows. Burrows
are of two types: surface burrows for food gathering
and deeper burrows for food storage and shelter.
Pocket gophers do not hibernate, but stay in their
burrows in winter.
pocket gopher (Thomomys bottae, Geomyidae)
HB 5 to 7 inches; T 13/4 to 33/4 inches. This
animal is dark brown-gray above with a purplish
cast on its sides; lighter below. Its tail is
tan-gray and mostly hairless. It is active yearlong.
It is primarily nocturnal, rarely spending much
time above ground; it may be active day and/or
night below ground. It creates very extensive
burrows close to the surface, with its nest
deeper into the ground. The burrow tailings
form conspicuous mounds above ground. Botta's
pocket gopher occupies perennial meadows, grasslands,
and woodlands with moist, friable soils.
MICE are not really mice, but are more closely
related to ground squirrels and pocket gophers.
They occur only west of the Mississippi River.
They are nocturnal burrowers. They have external
fur-lined cheek pouches. They have moderately
long tails and short hind legs. Most do not hibernate.
pocket mouse (Chaetodipus (Perognathus)
californicus, Heteromyidae) HB 3 to 4 inches;
T 4 to 6 inches. The California pocket mouse
is brown-gray with white bristles/spines on
the rump and a brownish line along its side.
The very long tail is somewhat tufted and is
brown above and white below. Above ground, its
activity decreases during winter cold spells.
It inhabits chaparral and grassland communities,
especially where the two occur side by side.
It also occupies habitats within coastal scrub,
chaparral, and woodland communities.
WORLD MICE AND RELATIVES comprise the largest
family of mammals in North America. As would be
expected, there is considerable variety in habits
and form. Most species use burrows. None hibernates.
Based on dental structure, there are two groups:
cricetines (mice, deer mice, and woodrats) and
CRICETINE MICE have long tails and large
eyes and ears. Their teeth have well-developed
cusps. They are omnivorous and nocturnal.
harvest mouse (Reithrodontomys megalotis,
Cricetidae) HB 21/2 to 3 inches; T 2 to 4 inches.
This tiny mouse is brownish above, white below,
and buff-colored along the sides. Its incisors
are deeply grooved. It is active year-round.
Western harvest mice are active in late afternoon
and at night, especially on moonless and rainy
nights. They use the burrows of other rodents.
They are found especially in grassland, scrubland,
and woodland communities with water.
mouse (Peromyscus californicus, Cricetidae)
HB 41/2 to 5 inches; T 41/2 to 6 inches. The
California mouse is yellowish brown or gray
mixed with black above, whitish below, and often
has a buff-colored spot on its breast. It has
two rows of cusps on its teeth. It has internal
cheek pouches. It is active yearlong, though
it may undergo periods of torpor in times of
food shortage. It is nocturnal, its activity
level peaking just before dawn. It often lives
in the stick houses built by the dusky-footed
woodrat (Neotoma fuscipes). It occurs in mixed
or mature chaparral, coastal scrub, coastal
scrub interspersed with grassland, and coastal
live oak woodland, especially dense "oak-bay
mouse (Peromyscus maniculatus, Cricetidae)
HB 3 to 4 inches; T 13/4 to 43/4 inches. The
deer mouse is gray-reddish brown above and white
below. Its tail is bicolored and short-haired.
It has two rows of cusps on its teeth. It has
internal cheek pouches. It is active yearlong
and is nocturnal. It is ubiquitous, occupying
all habitat types, especially in woodland and
mouse (Peromyscus boylii, Cricetidae)
HB 31/2 to 43/4 inches; T 31/2 to 43/4 inches.
The brush mouse is brown-gray above; white below.
It has buff-colored-tawny sides. Its tail is
bicolored and hairy. It has two rows of cusps
on its teeth. It has internal cheek pouches.
It is active year-round and is nocturnal. Its
nest is made of dried vegetation under brush
piles or in rocky crevices. It inhabits chaparral,
especially mesic environments with dense shrub
and ground cover.
have large ears and look like overgrown deer mice.
They love anything shiny. They eat green vegetation,
as well as seeds, fruit, and nuts.
woodrat (Neotoma fuscipes, Cricetidae)
HB 6 to 7 inches; T 61/4 to 123/4 inches. This
woodrat is buff-brown above and gray-white below.
Its face is grayish. Its belly is often washed
with a tan color. Its feet are two-toned: a
dusky color with white toes. Its tail is brown
above and lighter below. It is active yearlong.
Mostly, it is nocturnal. It builds elaborate
stick houses on the ground or in trees. It inhabits
areas of dense, brushy understory, especially
if evergreen, in chaparral and coastal live
oak woodland communities.
woodrat (Neotoma lepida, Cricetidae)
HB 5 to 8 inches; T 33/4 to 71/2 inches. The
desert woodrat is buff-gray above and grayish
below. The tail is also bicolored. Its hind
feet are all white, whereas the dusky-footed
woodrat's are two-toned. All its fur is gray
at the base. It may take over the old burrow
of a ground squirrel, building up a stick house
around the entrance. It inhabits rocky slopes
in Yucca scrub communities.
are microtines with stout bodies, short legs and
tails, and tiny ears and eyes. Their teeth are
molarized (the crowns are flattened) which enables
them to grind the grasses and leaves that they
eat. They are active day and night and year-round.
vole (Microtus californicus, Cricetidae)
HB 43/4 to 51/2 inches; T 11/2 to 23/4 inches.
The California vole is grizzled brown with scattered
black hairs above and gray below. Its fur is
often white-tipped. Its feet are pale, and its
long tail is bicolored. It occupies varied habitats
with friable soils, especially in riparian and
dense annual grassland communities.
WORLD RATS AND MICE have long tails and large
ears. They differ from native rats and mice by
their molariform teeth which have three rows of
cusps instead of two. They are primarily nocturnal
and active year-round.
rat, ship rat (Rattus rattus, Muridae)
HB 61/2 to 8 inches; T 61/4 to 10 inches. The
black rat is brown or gray above and gray-whitish
below. Its tail is dark and scaly and has few
hairs. Although it is primarily nocturnal, it
is occasionally active by day. It is found primarily
in riparian communities, especially near human
homes and/or open dumps. It may also occur in
dense vegetation away from human habitation.
mouse (Mus musculus, Muridae) HB
21/2 to 33/4 inches; T 21/2 to 4 inches. The
house mouse is gray-brown above and nearly as
dark below. Its dusky-colored tail has few hairs.
It inhabits buildings and fields, as well as
ruderal herbaceous, shrubby, and riparian habitats
near human homes. The white lab mouse has been
bred from this species.
All have three pairs of upper and lower
incisors, as well as strong canines. Most are
carnivorous; many are omnivorous. None hibernates,
although some may spend considerable time in their
nests during the cold weather.
AND FOXES have a long, narrow muzzle, erect,
triangular ears, strong, thin legs, and a bushy
tail. They have excellent vision, hearing, and
sense of smell. Most chase down their prey, but
foxes also stalk and pounce.
(Canis latrans, Canidae) HB 291/2 to
361/2 inches; T 113/4 to 151/2 inches. The coyote
is 23-26 inches high at the shoulder and weighs
between 20 and 40 pounds. It is grizzled gray
or reddish gray with some buff color. Its legs
are rusty-yellowish in color; its lower foreleg
bears a dark vertical line. It has a bushy tail
with a black tip. Coyotes hunt in small groups
or in pairs. The coyote is active yearlong.
It is crepuscular and nocturnal, occasionally
diurnal. It occurs in open brush, scrub, and
herbaceous habitats, as well as open woodlands
with low to intermediate canopy and some shrub-grass
understory. It inhabits areas near free water.
fox (Urocyon cinereoargenteus, Canidae)
HB 223/4 to 27 inches; T 83/4 to 171/2 inches.
The gray fox is 14 to 15 inches high at the
shoulder and weighs between 7 and 13 pounds.
It is grizzled gray above and reddish below
and on the back of the head. It has a white
throat. Its tail is black above and at the tip.
It has rusty-colored feet. It is a solitary
animal. It is active yearlong, especially during
crepuscular and nocturnal hours. It is occasionally
diurnal. It occupies meadows and scrubland,
riparian, and woodland communities.
are distinguished by their masked faces and long,
banded tails. Their blunt teeth suggest that raccoons
are not strictly carnivores, but are well adapted
as omnivores. They have five clawed toes on each
foot and walk flat on the soles of their feet
(like bear and human). They may den in hollow
trees or caves, or use burrows in the ground.
They are social and stay in family groups. They
(Procyon lotor, Procyonidae) HB 161/4
to 211/2 inches; T 71/2 to 16 inches. The raccoon
weighs between 12 and 48 pounds. It is reddish
brown above with lots of black in its fur. Below
it is gray. Its bushy tail is banded (four to
six bands) in black and brown or black and gray.
The fur on its face is colored such that the
raccoon appears to be wearing a black mask outlined
in white. It stays in its nest when the weather
is very cold. The raccoon occurs in most habitats
whether natural or anthropogenic, especially
in riparian, scrubland, and woodland communities.
Water must be available nearby.
BADGERS, AND SKUNKS have paired anal scent
glands used, in weasels and badgers, for social
and sexual communication and, in skunks, for personal
defense. They have long bodies on short legs.
They have short, rounded ears. Their fur is very
soft. They are solitary. They are primarily nocturnal
and are active yearlong.
weasel (Mustela frenata, Mustelidae)
HB 8 to 151/4 inches; T 3 to 61/2 inches. The
long-tailed weasel weighs between 1/4 and just
over 1/2 pound. Its black nose and eyes are
bright against the brown face with some white
fur. It is reddish brown above and whitish below.
Its tail is brown with a black tip. The legs
seem very short in proportion to the rest of
the body. Its feet are brownish. It can be active
both day and night. It inhabits most areas except
the most extremely xeric ones. It uses a mixture
of habitats, especially in riparian woodland
and scrubland communities. Weasels are instrumental
in helping to control the rodent population,
but also eat other small mammals.
(Taxidea taxus, Mustelidae) HB 161/2
to 28 inches; T 4 to 6 inches. The badger weighs
between 8 and 25 pounds. Its flattish body has
short, bowed legs. It has shaggy fur that is
grizzled gray-brown. It has a white stripe from
its shoulder to its snout. Its cheeks are white
with a black patch. Its yellowish tail is short
and bushy. Its feet are dark, and it has large
fore claws. The badger can be active both night
and day. It may experience variable periods
of torpor in winter. It frequently digs in California
ground squirrel colonies; it is a powerful burrower.
It inhabits the open areas with dry, friable
soils in most scrubland, woodland, and herbaceous
communities. It hunts small mammals, especially
rodents, as well as birds, invertebrates, and
rattlesnakes. It also eats carrion.
skunk (Mephitis mephitis, Mustelidae)
HB 13 to 16 inches; T 7 to 151/2 inches. This
skunk weighs between 6 and 14 pounds. It is
mainly black. It has two broad white stripes
that run up its back and meet in a cap on its
head. There is a thin white stripe down the
center of its face. Its bushy black tail is
often fringed and/or tipped in white. Although
it is mainly nocturnal, it may occasionally
be crepuscular. It is found in nearly all habitats,
especially in riparian woodland and herbaceous
and grassy habitats in most communities and
their ecotones. It is common in anthropogenic
communities. Skunks are omnivorous.
are sleek animals with strong legs. They have
short, somewhat rounded ears, long, sensitive
whiskers, and eyes facing forward. They have excellent
night vision. Their teeth are well adapted for
their carnivorous lifestyle: the molariform teeth
have shearing edges, and the canine teeth are
large fangs. Their fore feet have five toes, their
hind feet have four, all with retractile claws.
Their foot pads are soft, enabling them to silently
stalk their prey. Most are nocturnal and solitary,
except during mating season. They are active year-round.
lion, cougar, puma (Felis concolor,
Felidae) HB 38 to 72 inches; T 21 to 36 inches.
The mountain lion weighs between 75 and 275
pounds. It is yellowish-tawny above and white
under buff below. Adults are not spotted, but
juveniles are buff with black spotting. The
long tail is black-tipped. Mountain lions are
mostly nocturnal and crepuscular. They inhabit
most areas, especially riparian and brushy areas
of most communities in Poly Canyon.
(Felis rufus, Felidae) HB 24 to 44 inches;
T 4 to 7 inches. The bobcat weighs between 14
and 68 pounds. It is tawny-colored (grayer in
winter), with indistinct blackish spotting.
It has a short, stubby tail with two to three
bars and a black tip above, white below. Its
upper legs have dark horizontal bars. Its face
has thin black lines that radiate onto its broad
cheek ruff. Its ears are somewhat tufted, though
this is difficult to see at a distance. It is
mostly nocturnal and crepuscular, although it
may also be active by day. It inhabits most
areas, especially brushy riparian and coastal
live oak woodland communities, as well as chaparral.
It also forages in grasslands.
In Poly Canyon, the only EVEN-TOED HOOFED MAMMAL
is the mule deer. It is herbivorous, and its molariform
teeth are well adapted for grinding vegetation.
Also, even-toed hoofed mammals have a cartilaginous
pad instead of incisors at the front of their
upper jaw. Males have antlers that are made of
bone and are shed each year. Antlers become larger
and have more points each year until the individual
reaches maturity. Females are generally smaller
than males. Fawns have spotted coats.
deer, black-tailed deer (Odocoileus hemionus,
Cervidae) HB 31/2 to 53/4 feet; T 41/2 to 9
inches. The mule deer is 3 to 31/2 feet high
at the shoulder. Males weigh between 110 and
475 pounds; females weigh between 70 and 160
pounds. In summer mule deer are reddish or yellowish
brown above; in winter they become grayer above.
They are creamy-tan below. The tail is white
above and tipped with black (mule deer) or is
blackish/brownish above and to the tip (black-tailed
deer). It is active yearlong. It is usually
crepuscular, but may be active day or night.
It is found in woodland and scrubland habitats,
especially in a mosaic of various-aged vegetation
that provides wooded areas for cover, meadows
and shrubby clearings for feeding, and free