|The Mammals of Texas -
Botta's Pocket Gopher
Rodentia : Family Geomyidae : Thomomys
bottae (Eydoux and Gervais)
Description. A medium-sized rodent with
external, furlined cheek pouches; the outer face of the
upper incisors lacks conspicuous grooves; claws on front
feet relatively small (less than 10 mm long); upperparts
varying from pale gray to russet and blackish; underparts
grayish-white, white, buffy, or mottled. External
measurements average: (males), total length, 267 mm;
tail, 81 mm; hind foot, 33 mm; (females), 219-69-28 mm.
Weight (males), 160-250 g; (females), 120-200 g.
Distribution in Texas. Trans-Pecos Texas
and eastward across the Edwards Plateau and immediately
adjacent areas to Mason County.
Habits. Pocket gophers of this
species are extremely adaptable as regards habitat. They
occur in soils ranging from loose sands and silts to
tight clays and in vegetative zones grading from dry
deserts to montane meadows. Perhaps one reason why they
can tolerate such environmental extremes is that they
spend fully 90% of their lives in underground burrows,
secure from the elements.
Their burrow systems are often
complicated structures consisting of two or more main
galleries and several side chambers. A partly excavated
burrow extended more than 30 m in length, had four main
"forks," and averaged 6 cm beneath the surface,
although the tunnel leading to the nest descended to a
depth of more than 60 cm. Tunnel systems more than 150 m
in length are not rare. These ramified travelways
probably help the occupants to avoid predators that try
to search them out; they are equally important in
permitting the gopher to forage over a considerable area
without exposing itself unduly to danger. Special side
branches serve as storehouses for food, others as
repositories for refuse and fecal pellets. In winter,
when snow covers the ground, the gophers often extend
their burrows into the snow and can then forage
aboveground in safety.
Although pocket gophers are active the
year round, they store food to carry them over periods of
scarcity, especially periods of drought when food is
scarce and burrowing a difficult task. Usually, only one
adult animal occupies each burrow system except for a
short time in the breeding period. Associated with this
solitary habit is a ferocious and seemingly fearless
disposition. When two gophers encounter each other, they
either fight or meticulously avoid each other. Desire for
companionship seems to be completely lacking in their
They feed on a variety of foods, but
fleshy roots and tubers are their main reliance. Unlike Geomys bursarius, Bottas pocket gophers often come to the
surface to feed and clip off vegetation around the burrow
as far as they can reach in all directions without losing
physical contact with the opening. If molested the
animals back into the burrows with amazing speed. At
other times, they approach desirable plants from below
and pull the entire upperparts into the burrow where they
can be cut up and stored or eaten at leisure. The roots
of alfalfa are especially prized, but almost any native
plant is potential food.
The nest is a compact, hollow ball of
dry, shredded vegetation placed in a special chamber off
the main gallery, about 30-70 cm beneath the surface of
the ground. Both sexes build nests as sleeping quarters.
This species breeds continuously, with
three marked periods of increased fertility
spring, summer, and early winter. The main breeding
season is in spring, however; summer breeding is mainly
by young females, possibly those born the preceding
spring. The winter season is one of slight breeding
activity and often merges with the one in early spring.
Old females produce yearly an average of two litters of
five young each; young females are less fecund. The young
are blind, naked, unpigmented, and weigh about 4 g at
birth. The ears are poorly developed, but the cheek
pouches are fully formed although smaller proportionately
than in adults. Growth appears to be relatively slow, but
details of this phase of their life history are lacking.
In cultivated areas, pocket gophers may
be destructive and require control by trapping or
poisoning, but on natural lands they are of decided
benefit as soil builders. They are the chief natural
cultivators of soils, and the maximum thrift of wild
vegetation is dependent upon their continued activity.
Photo credit: John L. Tveten.