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Exploring the beautiful nature of California
California Nature: Gophers
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Pocket gophers, often called gophers,
Thomomys species, are burrowing rodents that get their name
from the fur-lined, external cheek pouches, or pockets, they use
for carrying food and nesting materials. Pocket gophers are well
equipped for a digging, tunneling lifestyle with their
powerfully built forequarters; large-clawed front paws; fine,
short fur that doesn’t cake in wet soils; small eyes and ears;
and highly sensitive facial whiskers that assist with moving
about in the dark. A gopher’s lips also are unusually adapted
for their lifestyle; they can close them behind their four large
incisor teeth to keep dirt out of their mouths when using their
teeth for digging.
Five species of pocket gophers are found in
California, with Botta’s pocket gopher, being most
widespread. Depending on the species, they are 6 to 10 inches
long. For the most part, gophers remain underground in their
burrow system, although you’ll sometimes see them feeding at the
edge of an open burrow, pushing dirt out of a burrow, or moving
to a new area.
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Pocket gophers live in a burrow system that can
cover an area that is 200 to 2,000 square feet.
The burrows are about 2–1/2 to 3–1/2 inches in
diameter. Feeding burrows usually are 6 to 12
inches below ground, and the nest and food
storage chamber can be as deep as 6 feet.
Gophers seal the openings to the burrow system
with earthen plugs. Short, sloping lateral
tunnels connect the main burrow system to the
surface; gophers create these while pushing dirt
to the surface to construct the main tunnel.
Gophers usually live alone within their burrow
system, except when females are caring for their
young or during breeding season. Gopher
densities can be as high as 60 or more per acre
in irrigated alfalfa fields or in vineyards.
Gophers reach sexual maturity about 1 year of
age and can live up to 3 years.
In non-irrigated areas, breeding usually occurs
in late winter and early spring, resulting in 1
litter per year; in irrigated sites, gophers can
produce up to 3 litters per year. Litters
usually average 5 to 6 young.
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Pocket gophers are herbivorous and feed on a wide variety of
vegetation but generally prefer herbaceous plants, shrubs, and
trees. Gophers use their sense of smell to locate food. Most
commonly they feed on roots and fleshy portions of plants they
encounter while digging. However, they sometimes feed
aboveground, venturing only a body length or so from their
tunnel opening.
Burrow openings used in this manner are called “feed holes.” You
can identify them by the absence of a dirt mound and by a
circular band of clipped vegetation around the hole. Gophers
also will pull entire plants into their tunnel from below. In
snow-covered regions, gophers can feed on bark several feet up a
tree by burrowing through the snow.
Pocket gophers are beautifully adapted for life underground.
These chestnut-colored rodents have small ears and eyes, and can
chew and dig their way through compacted soil and roots with the
help of large, incisor teeth and long, curved claws on enlarged
forelimbs.
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The lips close behind the front teeth, which prevents dirt from
entering the mouth. The "pocket" part of their common name
refers to two fur-lined cheek pockets or pouches, which have
external openings on either side of the mouth.
The pouches are used to transport food and nest material. Pocket
gophers are only 10-12 inches long from nose to tip of tail but
they are capable of digging tunnel systems that may extend for
500 feet or more, although 145 feet is the norm. As they dig,
they push piles of loose dirt to the surface, a characteristic
that has earned them the name "sandy mounders".
Shallow tunnels generally run parallel to the surface and
provide access to their diet of roots and tubers, while nest and
food storage tunnels are deeper. Pocket gophers plug tunnel
openings to prevent snakes and other predators from entering.
Pocket gophers are solitary animals and, except for females
nursing young, do not share a tunnel system.
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Mounds of fresh soil are the best sign of a gopher’s presence. Gophers form
mounds as
they dig tunnels and push the loose dirt to the surface. Typically mounds are
crescent or horseshoe shaped when viewed from above. The hole, which is off to
one side of the mound, usually is plugged.
Mole mounds
are sometimes mistaken for gopher mounds. Mole mounds, however, are more
circular and have a plug in the middle that might not be distinct; in profile
they are volcano-shaped.
Unlike gophers, moles commonly burrow just beneath the
surface, leaving a raised ridge to mark their path. One gopher can create several mounds in a day. In nonirrigated areas, mound
building is most pronounced during spring or fall when the soil is moist and
easy to dig. In irrigated areas such as lawns, flower beds, and gardens, digging
conditions usually are optimal year round, and mounds can appear at any time. In
snowy regions, gophers create burrows in the snow, resulting in long, earthen
cores on the surface when the snow melts. |
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Gophers
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