200 years: toxic baits have killed billions of prairie dogs,
and recreational shooting has eliminated millions more.
Where Have All the Prairie Dogs Gone?
In the 1800s, the geographic range of prairie dogs encom-
passed more than 160 million hectares, and extended from
southern Canada to northern Mexico and from eastern Ne-
braska to the foothills of the Rocky Mountains (Hollister
1916; Hall 1981; Proctor et al. 2005). Prairie dogs did
not live everywhere in this huge range, but rather inhabited
about 30 million of the 160 million hectares. Today’s prai-
rie dogs, however, inhabit only 0.5 – 0.8 million hectares,
and over two-thirds live in small, isolated colonies (USFWS
2000; Lomolino and Smith 2003; Proctor et al. 2006). As
explained in the following, at least five factors have contrib-
uted to the decline of prairie dog numbers, and these factors
are sometimes synergistic (Wuerthner 1997; Manes 2006).
Before converting a colony site to cropland, for example,
the landowner might first poison all the prairie dogs. Sev-
eral of these factors have contributed to the rarity of other
ground-dwelling squirrels (e.g., Yensen and Sherman 1997,
2003).
Destruction of suitable habitat
Approximately one-third of the suitable habitat within the
former geographic range of prairie dogs has disappeared
over the last 200 years (Mac et al. 1998; Manes 2005; Proc-
tor et al. 2006). Most of the destruction of habitat has in-
volved conversion to cropland, but conversion to accommo-
date industry, urbanization, and livestock also has occurred.
Poisoning
The first organized campaign to poison prairie dogs began
in Texas in the late 1890s (Palmer 1899; Knowles 1986a).
By the 1920s, federal programs to kill prairie dogs were
operational in every state where they lived. The numbers
of victimized prairie dogs are staggering. In 1923 alone,
for example, 1.5 million hectares inhabited by prairie
dogs were poisoned (Forrest and Luchsinger 2006). And
from 1912 through 1923 in Colorado, approximately
30,000,000 prairie dogs were killed by 595,926 liters of
strychnine-treated grain (Clark 1989).
Recreational shooting
Shooting of prairie dogs in western states has occurred for
100 years (Smith 1967). People sometimes shoot prairie
dogs for food, but most shooting has been, and continues
to be, primarily for recreation /sport. By itself, recreational
shooting probably has not seriously depressed populations
of prairie dogs over the last century. The combination of
poisoning with follow-up shooting, however, sometimes
eradicates small colonies (Reeve and Vosburgh 2006).
In the last decade or so, recreational shooting of prairie
dogs has begun to attract marksmen with high-technology,
long-range rifles, some of which enable accuracy from
1,350 meters. In North Dakota, for example, the num-
ber of out-of-state recreational shooters increased from 163
in 1989 to 1,326 in 2001 (Reeve and Vosburgh 2006). With
this greater interest and better weaponry, the toll from rec-
reational shooting can be substantial. In South Dakota in
2000, for example, recreational shooting eliminated 1.2 mil-
lion prairie dogs (Reeve and Vosburgh 2006).Prairie dogs as pets
If captured when young, prairie dogs make excellent pets
(Ferrara 1985). Prairie dogs do not readily breed under
laboratory or pet-store conditions, however, and catching
juveniles in the wild is arduous. Further, prairie dogs some-
times transmit diseases such as plague and monkeypox
to humans (Long et al. 2006). Consequently, the commerce
of pet prairie dogs has been dormant for most of the last
200 years. In the late 1990s, however, Gary Balfour de-
signed a truck that can vacuum young prairie dogs from
their natal burrows (Long et al. 2006). Capturing large
numbers of juveniles from the wild is now relatively easy,
and national and international interest in prairie dogs as
pets has skyrocketed. The pet trade thus poses another ob-
stacle to the long-term survival of prairie dogs. Pets increase
public awareness of the charm and importance of prairie
dogs, however. Pet owners thus might be more likely to sup-
port efforts to save prairie dogs from extinction. The over-
all effect of the pet industry on the conservation of prairie
dogs is unclear (Miller and Reading 2006).Plague
Plague (called sylvatic plaguewhen it occurs among wild
rodents) is another factor responsible for recent population
crashes among prairie dogs. Plague is caused by a bacterium
(Yersinia pestis),and fleas (Siphonaptera) are its most com-
mon vectors (Barnes 1993; Hoogland et al. 2004). Plague
probably arrived into the United States about 100 years ago
via flea-infested rats from Asian ships; the first incidence of
plague among prairie dogs occurred in the 1940s (Pollitzer
1951; Biggins and Kosoy 2001; Cully et al. 2006). Perhaps
because of this short exposure to an introduced disease,Conservation of Prairie Dogs 473