(Geomys sp.) This
fuzzy little fellow was spotted scurrying across Dove Key Ranch one evening after
a large rainstorm. Since pocket gophers rarely leave their burrows (see below),
I quickly grabbed him up to ensure he was not injured or sick in any way. Three
species of geomyids (Attwater’s (G. attwateri), Baird’s (G. breviceps),
and Plains (G. bursarius) Pocket Gopher) inhabit our area, all almost identical
morphologically, making it nearly impossible to establish to which species our
muddy neighbor belonged without a genetic analysis. However, he was given a clean
bill of health and released in hopes that he would reconstruct a tunnel system
higher than the water table next time.
Photo courtesy Dove Key Ranch Wildlife Rehabilitation
Gophers in Texas:
Nine species of
pocket gophers populate the subterranean world of Texas. Three of these (the Llano
(G. texensis), the Texas (G. personatus), and the Attwater’s (G.
attwateri) Pocket Gopher) are entirely endemic to the Lone Star state. With
the exception of some geographical variation and difference in tooth morphology,
the only way to distinguish among taxa is through their genetic variation.
generic name Geomys means “earth mice,” and these hard-working excavators are
perfectly suited to life underground. Tiny ears and eyes, truncated necks, and
sleek fur that can be arranged either backwards or forwards make for easy movement
through the soil. A muscular upper body and front legs terminating in long, curved
claws (see picture above) join long incisors as formidable earth-moving equipment.
When loamy soil and loose sands give way to rougher substrates or tangles of tree
roots, pocket gophers switch gears from digging with their powerful fore feet
to chiseling through obstacles with their elongated front teeth. While the idea
of crunching through dirt with teeth may make humans cringe and set our dentists
on speed-dial, not only are gopher incisors constantly growing to adjust for the
erosion from their daily labor, but the front of their chompers are also coated
with a thick layer of enamel. As the small rodent channels through the earth,
the back of his/her teeth wear faster than the enamel-protected front, resulting
in a continually resharpening chisel edge for digging.
A geomyid’s incisors
are always exposed, leading to the development of the “pocket” of their common
name: a fur-lined cheek pouch between the gopher’s cutting tools and tightly sealed
lips. These handy compartments allow the vegetarian miner to carry plant leftovers
to underground storage chambers, where the gopher uses his/her forepaws to push
out the pocket’s contents and thoroughly clean the furred shopping bag, concluding
the whole maneuver by pulling the pouch back into place with a specialized muscle.
Everything a pocket gopher does is underground: foraging, sleeping, raising
young, and even mating. In rare cases, the squinty-eyed rodents may seek out a
favorite veggie snack on the surface, but they often stay within a tail’s length
of their burrow, only venturing farther when displaced by flooding rains or persistent
digging predators such as coyotes, striped skunks, or badgers.
to stock their stomachs and subterranean larders, pocket gophers excavate shallow
tunnels, which allow them to perform the ever-popular magic trick: disappearing
plant. One second the poppy mallow’s there, the next second, it’s completely gone.
You may convince yourself that you’re suffering from some sort of heat-induced
hallucination, but rather you should consider yourself fortunate to have witnessed
a pocket gopher’s snack attack. Once a geomyid has finished processing whatever
delicious root or tuber it has encountered along its route, the diner may pull
the rest of the plant completely into its tunnel in order to finish off the meal
or transport the remainder to a deeper pantry. Surficial burrows are only for
satisfying the pocket gopher’s feeding requirements. Deep below these are more
extensive tunnel systems that are witness to the rest of the geomyid’s life. Different
chambers for food storage, nesting, and waste stretch through the earth below,
the clues of which are only visible to surface-dwellers in the mounds of soil
pushed to the heavens atop the chests and heads of these underground architects.
Subsurface tunnels also facilitate regeneration of the species. Male pocket
gophers frantically burrow their way to females in the mood, quickly impregnate
them, and then dig away to the next willing mate. Other than this brief seasonal
encounter, geomyids rarely spend time with any individuals of their species after
they wean from their mother’s care. In fact, if one pocket gopher encounters another,
initial wheeze-filled warnings and gnashing teeth may escalate into a fight to
Despite their reclusive nature, these industrious mammals are
contributing a priceless service to the ecosystems on which farmers, ranchers,
and even backyard gardeners depend. The tunnelings of pocket gophers aerate the
soil through which they travel, which fosters better plant growth. Their subterranean
dwellings also reduce erosion and aid in the conservation of groundwater.
So, the next time that you stumble across a hefty mound of dirt or a shallow network
of burrows, don’t disparage the small excavators who led to their creation. Instead,
thank your luck that Texas’ native pocket gophers are working to make your land
more productive and adding a little excitement to the subterranean soap opera
beneath your feet.
January 16, 2011
Dove Key Ranch Wildlife Rehabilitation - "Animal
of the Month" Series