Black-tailed Prairie Dog

Cynomys ludovicianus (Cynomys comes from Greek words meaning "dog mouse" due to it’s dog-like bark)

Currently at PHX Zoo: #8956 Female “Old Lady” – Has cataracts in both

eyes.

Order: Rodentia

Family: Sciuridae

Genus: Cynomys

Sub-genus: same (generally for black-tipped tails)

Species: ludovicianus (1817 named)

Related species: Sub-genus Leucocrossuromys is gen. for white-tipped tails; this is the only “black-tipped tail” PD

Length: 14–16 3/8" (355–415 mm); Tail 2 7/8–4 1/2" (72–115 mm)

Weight: 32–48 oz (900–1,360 g)

Note: considered largest of the spp. Smaller Gunnison’s PD is most widely seen in AZ.

Coloration: pinkish brown above to protect from sun; whitish or buffy white underparts.

Vocalization: Highly vocal: Studies with a sound spectrogram indicate that it has 11 distinctive calls, including chirps and chatters much like those of a tree squirrel; snarls, used when fighting; squeals of fright; and a shrill bark that gives this animal its common and genus names. A staccato, double-noted call consisting of a chirp followed by a wheezing sound and accompanied by tail flicking is an alarm signal; it is chorused by other prairie dogs before all dive for safety. The "jump-yip" display, in which the prairie dog leaps into the air with head thrown back and forelegs raised as it gives a wheezing, whistling yip, seems to be an all-clear signal; this is also picked up by other prairie dogs, and soon the whole community is jumping and yipping.

Senses: Small ears, very good hearing; large eyes positioned on the sides of the head, appear to be adapted for detecting movement over a wide arc, and this allows for predator detection

Dentition: 22 teeth (1/1 0/0 2/1 3/3)

Body parts: Adapted for fossorial life (underground) w/ short legs for burrows & long sharp claws for digging.

Mating season: late winter, early spring, February–March.

Parental care: altricial: born deaf, blind and hairless, don’t emerge from burrow until 6 wks. old. Males amicable to all young; females highly territorial and aggressive within cotery during nursing period.

Gestation period: 28-36 days

Weaning period: They begin fending for themselves at about 10 weeks, and are fully grown at six months.

Sexual maturity: 2 years

# of young: 1 litter per year of usually 1-8 young but usually only 3 survive to emerge from burrow.

**Special note: Female mothers commit infanticide on offspring of related mothers in coterie. 39% of litters are eliminated this way. Only mammal with this behavior.**

Social structure: Highly structured & colonial. 1 male, 3-4 adult females, several yearling, juveniles (1-2 yrs.) make up a coterie, usually about 9 but can be up to 26 individuals. A ward consists of several coteries; a town is several wards. Colony or town can cover 100 ha (or 250 acres)

Life span: 7-8 yrs.

Diet: 98% consists of forbs & grasses such as grama grass, bluegrass, bromegrass. Occasionally eats a few insects, esp. grasshoppers & rarely eats meat.

Defensive adaptations: It habitually consumes all the green vegetation around its burrow, not only because it is convenient, but also to clear away protective cover that might shield predators. The burrows have conical entrance and exit mounds, which prevent flooding and serve as vantage points at which prairie dogs often sit on their haunches to survey their surroundings and scan for danger. Also stop eating every 10 sec. to look for predators.

Predators: Black-footed ferret before their numbers dwindled. Now foxes and the American badger are this prairie dog’s chief predators, but coyotes, bobcats, eagles, hawks, and snakes also take a share.

Habitat & Range: Widest distribution of all spp. Shortgrass prairies from Eastern Montana and SW North Dakota south to extreme SE Arizona, New Mexico, and NW Texas.

Primary risk factors:

--Control by poisoning, not as widespread as in the past but still sanctioned by govt. agencies

--Habitat destruction through cropland conversion and urbanization

--Sport or recreational shooting since all states in historic range of PD consider them pests

--Disease, mainly slyvatic (bubonic) plague transmitted by fleas.

Current status: Up for consideration as threatened status but not high enough priority for endangered list at this time (7/02). See http://www.r6.fws.gov/btprairiedog/ for USFWS status review. Population has been reduced to 2% the original area they occupied prior to 1870 due to govt. supported extermination efforts that are still occurring. Last largest single town of PD covering 110,000 ha in S.D. was eradicated in 1987-88 by poisoning. Two related spp. are endangered or threatened due to similar risk factors. See National Wildlife Research Center (http://www.aphis.usda.gov/ws/nwrc/index.html) for efforts to control PD.

Conservation summary: PD compete with cattle for grasses and forbs; however, it takes about 400 PD to equal 1 cow with calf’s grazing needs. Also PD increase health and viability of several grass species so are healthier for cattle grazing while maintaining grassland & savannah ecosystem. Decline of dependent spp. like Black-footed ferret was predicted in 1926. Efforts to increase population of this primary predator are improving; however, protection of prairie dogs as major food source or habitat of ferrets is slow going. PD are also extremely susceptible to plague bacterium showing a 100% mortality rate.

Unique facts:

--origin of name Cynomys from dog-like bark

--mothers of coterie** often seek out young of other females to kill and devour; about 39% of all litters are destroyed by infanticide. Unique among mammals & significance is unclear. (Walker, p.1260)

--more highly evolved than other spp. due to grooming, vocalizations, and highly structured society

--only Cynomys PD are active year-round and merely go torpid under inclement conditions

--over 170 other species depend on the habitat of PD towns: a few are burrowing owls, badger, sharp-shinned hawk, ornate box turtle, scissor-tailed flycatcher, therefore termed a “keystone species”

--create burrows for scat which they cover up with dirt and when chamber is full they dig another one

--illegal to possess in Arizona

References:

Nowak, Ronald M. Walker’s Mammals of the World. Baltimore: Johns

Hopkins University Press, 1999.

Brian Miller, Richard P. Reading, and Steve Forrest. Prairie Night: black-footed ferrets and the recovery of endangered species. Washington, DC : Smithsonian Institution Press, 1996.

http://fws.gov -- U.S. Fish and Wildlife Service

Other sites of interest:

National Wildlife Federation information (http://www.nwf.org/prairiedogs/)

NWF’s down-loadable picture (http://www.nwf.org/prairiedogs/pdog.jpg)

Mammals of Texas online edition (http://www.nsrl.ttu.edu/tmot1/cynoludo.htm)

Desert USA—Ultimate Desert Resource

(http://www.desertusa.com/dec96/du_pdogs.html)

Black-tailed Prairie Dog MVM 8/28/02