MAMMALS IN HERCULES
CHARACTERISTICS
1.
Females possess mammary glands which provide milk
for their young.
2.
Possess hair or fur.
3.
Most have varied teeth for cutting, tearing or grinding.
4.
Warm-blooded and back-boned (also in birds).
5.
Ends of digits usually have claws, nails or hoofs.
6.
External ear flap.
7.
Movable upper eyelids.
Mammals keep warm under a coat of
hair or fur. To protect against winter temperatures, many mammals develop
thicker, longer fur. This extra fur is shed in the spring with the onslaught of
warmer weather. Deer get extra insulation from the trapped air inside their
hollow hairs. Mammals can control body temperature so that it stays fairly
constant by panting, sweating, and confining activity to the cooler hours. Not
all mammals have the same body temperature. It generally varies quite a bit
among different groups of mammals. Mammals, in any environment, that are active
by night and quiet by day are called nocturnal.
Antlers and Horns
Some mammals have antlers or horns
growing from their skulls. Male members of the deer family produce antlers.
Antlers grow externally from calcium deposited by blood-filled capillaries
underneath furred skin. By late summer, growth stops and the furry skin, called
velvet, is rubbed off against tree trunks and small saplings. Antlers are
sharpened for use and display during the fall mating season. They are shed in
winter with regrowth starting in the spring.
Evergrowing Teeth
Rabbits and rodents have incisors
that grow continuously, an adaptation to grit in their diet which would
otherwise wear their teeth to the gumline. Evergrowing teeth are kept under
control normally by grit, or by gnawing action. If these animals don’t have
enough grit in their food, or are unable to gnaw regularly, their incisors will
grow outside of their skulls and protrude from their mouths. If unchecked,
these teeth will continue to grow until they turn backwards towards the skull,
preventing the animal from eating. Starvation and death result.
Skin Glands
Mammals have five different kinds
of skin glands, which serve specific purposes. Mammary glands in females
produce milk to nurse young. Sweat glands help to cool mammals and get rid of
waste products through the pores of the skin. Oil glands lubricate skin and
hair. Scent and musk glands produce chemicals used for marking territories and
communication.
Parasite Hitch-hikers
Wild
mammals support a wide variety of hitch-hiking parasites like fleas, ticks,
bloodsucking flies, and lice. Parasites can weaken their hosts, but rarely kill
them. Because some of these parasites can transmit diseases like plague and
tularemia to people, it is a good idea to avoid handling dead animals,
especially rodents and rabbits.
Coyote (Canis latrans)
Color
and size variable. Mountain coyotes are larger, have longer fur than desert
coyotes. Coyote is vocal at night; a series of yaps, a long howl, then short
yaps. Holds tail between legs when running. Can reach 40 mph. Track like a
dog’s. Population, range increasing despite hunting, poisoning campaigns.
Widespread. Dens along river banks, well drained sides of canyons, gulches. May
enlarge badger or squirrel burrows. Chiefly nocturnal, but active any time.
Often hunts in pairs. Omnivorous, but mostly eats small rodents, rabbits,
squirrels. Droppings gray, with some seeds, but mostly fur, bones, insect
parts, reptile skin, feathers; occasionally solid foil, plastic, or grass,
which helps remove tapeworms. Mates January-February. Six to seven pups born
April to May, raised by both parents. Livestock losses blamed on coyotes often
the work of dogs. Coyotes kill many grass-eating rodents, earning them
protection from some ranchers.
Gray Fox (Urocyon cinereoagenteus)
Salt-and-pepper
gray with rusty neck, legs, feet. Less vocal than other foxes. Can run, in
short bursts, 28 mph. Only fox which climbs trees to escape or to hunt. Mainly
in woodland, chaparral. Dens in hollow trees, logs, under rock ledges, or in
culverts; may have several escape dens nearby. Den area often marked by
accumulation of droppings, bones. Gray fox is nocturnal, but often seen in day.
Eats small rodents, insects, birds, eggs, fruit, acorns; in some areas, diet is
largely cottontail rabbits, ground squirrels, berries. Two to seven pups are
born March-April, dark brown, eyes closed. Hunt on their own at four months.
Afflicted with many diseases, parasitic worms. Enemies: domestic dogs, bobcats,
lions, people. Poison bait intended for coyotes kills many gray foxes.
Droppings: 50mm, 10mm, smaller
than
Coyote’s- almost always black
with stringy
Ends, berry seeds, fur, etc.
Mule Deer or Black-Tailed
Deer (Odocoileus hemionus)
Coat
varies; reddish in summer, grayish in winter. Have large ears that move independently
and almost constantly and account for the common name. Tail white with black
tip, to all black. Rump patch white. 100-475 pounds. Antlers branched; number
of branches and rack size increase with age, decline after peak; are shed in
winter; grown again in early spring, are covered with velvet until late summer.
Buck damages saplings and branches by rubbing off velvet. Black-tailed deer
are active most hours except mid-day.
Chiefly a browser; fond of clover, alfalfa, fruit, acorns, many herbaceous
plants.
Coastal
deer lose weight June-November, followed by natural die-off. Survivors gain
weight after fall rains. Shrubs resprouting after fires in the fall, combined
with available acorns, supply deer with essential food for recovery.
Bucks
solitary; may form bands before and after mating season. Harems form in
October. After gestation of 6-7 months spotted, odorless fawns are born
May-June, hidden for one month. Young does have singles, older does twins. Fawn
yearlings travel in family groups with mothers. Bucks will urinate in beds as
they stand; does step to one side first. Chief enemies; lions, bobcats,
coyotes, domestic dogs, people and cars.
Striped Skunk (Mephitis mephitis)
Bold coloring warns predators. When threatened may
snarl, stamp feet, raise hindlegs, click teeth, arch tail, turn toward enemy,
This failing, shoots a jet spray of musk (to 4.5 meters) as final defense.
Adult skunk needs about l0 acres. Uses abandoned burrows of other animals, digs
its own or may use protected spaces under houses (unless repelled by
mothballs). Nocturnal. Does not hibernate; may be inactive for weeks in winter.
Males solitary; females may den together in winter. Eats variety of vegetable
matter, insects, grubs, mice, eggs, frogs, and also yellow jackets and their
nests, leaving large holes in ground. Four to seven young born in May, follow
mother single-file until June or July. Chief carrier of rabies. Predators:
great horned owls, golden eagles.
Raccoon (Procyon lotor)
Color
salt-and-pepper. Playful, curious, good swimmer. Feeds mostly along streams,
lakes, ponds, but will wander from water. Dens in hollow trees, logs, rock
crevices, or ground burrows. In cold weather, may sleep for several days; does
not hibernate. Chiefly nocturnal, but occasionally about in day. Especially
active in autumn. Solitary except when breeding, caring for young. Diet varied:
fruits, nuts, grains, insects, frogs, fish, crayfish, birds’ eggs. Washing food
enhances sense of touch in toes, helps raccoon discern non-edible matter.
Leaves droppings at base of den tree, on large branches, rocks, logs across
streams. Mates in February or March. Two to seven young born April or May. In
fall, young raccoons may disperse up to 160 miles, but mostly less than 30
miles. Chief enemies: dogs, hunters, autos. Raccoon can defend self well
against a single dog.
hind feet
tracks: 95mm
droppings: 30 – 50mm
Opossum (Didelphis marsupialis)
Only
pouched mammal in U.S. Scruffy, gray body with prehensile tail. Thin, black,
hairless ears and part of tail may be missing in north range due to freezing.
Opossum feigns death when threatened. Thrives in urban, rural, and woodland
areas. Nests in hollow trees, logs, culverts, brush piles, under houses. Eats
fruit, vegetables, nuts, insects, carrion, eggs. Nocturnal. Solitary. Does not
hibernate; stays in den for several weeks in cold weather. Has one to two
litters, January to October. One to 14 embryos crawl out of womb to pouch
covering 13 teats. All could fit in a teaspoon. Nurse for two months. Five to
seven normally survive to juvenile stage. Lifespan about seven years.
Mountain Lion, Cougar, Puma (Felis
concolor)
Yellowish,
grayish, reddish-tawny. Habitat generally wilderness but may hunt in rural
hills. Male may travel 25 miles in one night. Strongly territorial. Mostly
nocturnal. Rarely seen. Voice like tomcat’s, greatly magnified. Uses tree
trunks as scratching posts. Solitary, except in two week breeding season. Eats
large mammals; one deer per week forms half of diet. Has more success catching
old, weak, less alert deer, thus keeps herd healthy. Also eats coyotes,
porcupines, beavers, rabbits, marmots, raccoons, birds, sometimes livestock.
Covers remains of large kill with branches, leaves. Droppings often left like
bobcat’s. Adults breed every two-three years. One to six furry, spotted kittens
Born
midsummer, raised by female for one to two years. Only enemies are human.
Before lions were legally protected, a man was found with 52 lion skulls, from
animals killed in the
Hind tracks: 101 mm
Droppings: 76 – 228 mm
Bobcat (Felis rufus)
Gray-brown
to reddish. Ear tufts used like antennae to aid hearing. Good climber. Gets
name from “bobbed” tail. Found in most every habitat, life zone. Range is
usually within two miles, may be up to 50 miles. Mostly nocturnal, also seen in
daytime. Solitary. Often rests on branches, atop large rocks to watch for
passing prey. Eats rabbits, mice, squirrels, porcupines, woodrats, bats, small,
weak deer. Caches large kills. Droppings are like dog’s or coyote’s, but often
partially buried, with scratch marks on ground. One to seven (average two to
three) kittens born April-May in den of dry leaves in hollow log, under rock
ledge or fallen tree. Southern animals may have two litters per year. Lifespan
25 years. Marks territory by urinating on rocks or tree trunks, making scent
posts. Uses tree trunk as scratching post. Often killed by poison bait intended
for coyotes.
Squirrels
There
are about 11 species of ground and tree squirrels. Most do not
hibernate, but sleep for short periods. Eat variety of green vegetation, seeds,
nuts, fruit, flowers, bulbs, roots, fungi, bird eggs, insects, baby birds, and
occasionally fresh road kills. Most store food for use after awakening from
sleep periods and in spring. Enemies include coyotes, foxes, bobcats, hawks, owls, and large snakes.
Western Gray Squirrel (Sciurus
griseus)
Large, gray (occasionally all
black), has bushy tail with white-tipped hairs. Belly white, or sometimes rust
colored. In oak and pine forests. Home range one half to two acres, two
squirrels per acre. Being displaced by introduced fox squirrel near urban
areas. Most active in mornings. Feeds heavily on fungi, robs acorn woodpeckers’
caches of acorns, eats pine nuts. Makes nests of sticks, leaves,
shredded bark in tree cavities or among outer branches more than five meters
above ground. Young born February, three to five per annual litter.
Fox Squirrel (Sciurus
Rusty, reddish gray, lower
parts rusty yellow or orange; some pure
Gray, no rust. Melanistic
forms occur. Introduced from east to
City parks and campuses, now
widespread in urban areas. Replaces native western gray squirrel as range
extends. Like western gray squirrel, buries acorns and pine nuts, some of which
are not retrieved and grow into trees. Young born February-March, sometimes
June-July, two to four per litter, with two litters per year. Lifespan about seven
years.
Desert Cottontail (Sylvilagus audubonii)
Dark
ear tips, larger size, and white-tipped hairs on underside distinguish it from
Brush Rabbits. In open plains, foothills, low valleys, coastal areas; in grass,
sage, moist chaparral. Home range one acre for females, up to 15 acres for
males. Active in late afternoon, night and early morning. Stays close to
thickets. Eats green vegetation and a variety of fruit, but rarely tree bark.
Young born naked and blind, in fur nests, throughout the year. May
Live
two years in wild. Vulnerable to marauding domestic dogs.
Brush Rabbit (Sylvilagus
bachmani)
Occupies
chaparral and thick brush of coastal and foothill areas. Stays close to
thickets, often clearing vegetation to bare ground along edges between brush
and grass areas. Home range ¼ to one
acre, with one to three rabbits per acre. Least active in middle of day, but
feeds on vegetation at any time. Basks in morning sun. Young born with short,
fine hair, but blind; two to six per litter, sometimes three to four litters
per year, January to June. Same enemies as other rabbits; also vulnerable to
dogs. Some tick species are specifically attracted to the ears of pregnant females
for their blood meal, which provides the hormones the ticks
Need
for reproduction.
Dusky-Footed Woodrat (Neotoma fuscipes)
Woodrat
often builds a second “escape” nest in tree branches near
Ground
nest. Presence of wood rats is indicated by bulky nests
Of
twigs at bases of trees, shrubs, in rock crevices, in cactus or
Tree
branches. They earned name ”packrat” by stashing anything
They
fancy in their nests. Nocturnal, territorial, they respond to
Disturbance
by drumming or thumping with hind feet or tails.
Woodrat
tails have hairs, unlike “old world rats”. Feed on green
Plants,
nuts, seeds, fruit, fungi. Most species give birth to one to
Four
young per annual litter. Enemies include owls, foxes, coyotes, bobcats and large
snakes.
(Microtus californicus)
Many
of the grass-covered hills, and often pastures and marshes as
Well,
are scenes of constant rodent activity. The grass is honeycombed with neat
tunnels, built and maintained by meadow mice. The floors of these tunnels are
smooth and well packed from daily use, and any debris in them is cleared away,
for a vole’s life often depends on a speedy and unobstructed retreat.
Meadow
voles are about 6 ½” long with a short (1 ½”) tail and small ears. Voles have
large families and they have them often. They can produce 12 litters a year,
4-8 in a litter. They are weaned at 10 days and the females can breed again.
Young females 4 weeks old and males 6 weeks old are ready to breed.
Fortunately, many predators – hawks, owls, snakes, weasels, skunks, badgers,
foxes, coyotes and bobcats – aid in keeping the vole population in check.
Without a high reproduction rate, the species would not survive.
Voles
usually eat their own weight every day—roots, grains, vegetables. Life span,
barring predation, is 11/2 years.
Botta Pocket Gopher (Thomomys
bottae)
Have
large, external, fur-lined cheek pouches for carrying food. Squeeze contents
out with fore paws; turn pouches inside out for cleaning. Burrowing area may
cover 2,000 square feet. Gopher’s lips close behind the upper incisors to keep
dirt out of mouths while they dig. Enamel covers fronts of incisors, creating
sharp, beveled edges as backs of teeth wear faster. Gophers are active day,
night, year round. Eat roots, tubers, greens. Solitary. Males fight other
gophers on contact, except females in breeding season.
Two species rarely live in same field. Sexually mature at three months. Young
born mainly in spring, one or two litters per year, 2 to 11 per litter.
Predation low. Enemies: badgers, weasels, snakes, owls, hawks, coyotes, foxes.
INSECTIVORES
The
insectivores, or insect-eating mammals, found in the bay region are shrews and
moles. Although there are six species of shrews in the bay region, they are so
much alike that positive identification of specimens should be sought from an
expert.
Shrew Mole (Neurotrichus
gibbsi)
The
shrew mole, smallest of North American moles, spends much of his time above ground
in a network of trails and tunnels beneath the leaves and tangled vegetation.
Identification Black,
forefeet longer than broad; tail relatively short, scaly, and haired. Head and
body 3 to 3 1/2" long; tail 1 to 1 1/2" long.
Habitat Moist ground litter
at edges of forest, around wet meadows,
and
along streams.
Range Restricted chiefly
to redwood forests.
Young Possible several
litters a year; 4 to 9 in a litter.
Food Earthworms, sow bugs
and insects.
Broad-Footed Mole (Scapanus latimanus)
Fur
blackish-brown or gray-brown, velvety, flexible; allows forward or backward
movement in tunnels with equal ease. Eyes pinhead size. Earholes concealed.
Naked nose is most vital sense organ. Mole digs with broad front feet in
breast-stroke motion. Can tunnel 30 cm.
per minute. Mounds appear to erupt from earth. Tunnel ridges collapse in
time; improve soil aeration, rain penetration, reduce erosion. Mole feeds on
worms, insects, centipedes, snails, slugs, some root crops. Young born
March-April, two to six per litter. Active day and night. Rarely above ground,
thus low predation rate.
A
mole run is often used only once. Thus a mole is hard to trap unless the trap
is set in one of his main tunnels, which are deeper and more often used (see
sketch). The dirt from these deeper tunnels is pushed to the surface in a
“molehill”; unlike a gopher’s mound, a molehill is never open.
Except
in the mating season, gophers are rarely found in the open, preferring
to remain in safety underground. Strong claws and chisel teeth equip them for a
life of burrowing. In hard soils they literally gnaw their way through the
ground.
Little Brown Bat
ORDER: CHIROPTERA
(“hand-wing”)
Myotis lucifugus
L.
31/2” Wing Span 9”
The
Little Brown Bat is one of the most common in
Rainforests
need bats for their survival to pollinate fruit flowers and disperse
seeds. Bats are responsible for 95% of
rainforest regeneration. If not for bats
we would not enjoy bananas, mangoes, plaintain, avocadoes, cashews, dates,
figs, allspice and many other fruits.
Nearly
40% of American bat species are threatened or endangered.
GLOSSARY
Carrion - Dead and decaying flesh.
Diurnal - Active during the daytime rather than at night.
Melanistic - Dark coloration of the skin, hair, fur, or feathers
because of a high concentration of melanin (dark pigments).
Nocturnal - Most active at night.
Omnivorous - Eating both animal and vegetable foods.
Prehensile - Adapted for seizing, grasping, or holding by
wrapping around an object.
Species - A group of plants or animals composed of
individuals that interbreed and produce similar offspring.
REFERENCES
Mammal Finder, Ron Russo and Pam Olhausen, Nature Study Guild,
Mammals of the
The Audubon Society
Field Guide to North American Mammals,
John O. Whitaker, Jr. Chanticleer Press,
Inc., N.Y., 1980
A Field Guide to the
Mammals, Peterson Field Guide
Sereies,
William H. Burt and Richard P.
Grossenheider
Illustrations scanned from
Mammal Finder, Ron Russo and Pam
Olhausen
