|
Pocket gopher
(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. |
Pocket Gopher
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.
The 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.
In order 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 the death.
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.
© Bonnie Wroblewski
http://www.dovekeywildlife.org
January 16, 2011
More Dove Key Ranch Wildlife Rehabilitation
- "Animal of the Month" Series |
|
|
HOME
