Gunnison's Prairie Dogs Research Articles

Reproduction, Growth and Development, and Behavior in the Mexican Prairie Dog, Cynomys mexicanus (Merriam)

Reproduction in C. mexicanus is unique among prairie dogs in that the reproductive season is extremely protracted, and may last for 6 months. The growth rate is equal to or greater than in other members of the genus. Molting in C. mexicanus is complex, involving four or more overlapping phases. Behavior patterns and vocalizations in C. mexicanus are most similar to those of C. ludovicianus. Alarm barks, chatter barks, growls, screams and elation calls of C. mexicanus show varying degrees of similarity to those of C. ludlovicianus. Considering the rapid development, it is estimated that C. mexicanus pups are capable of reproduction during their lst year. INTRODUCTION Although growth and development have been studied in numerous North American sciurid rodents (Clark, 1970), little information is available on the early postnatal growth and development in prairie dogs (Cynomys) prior to emergence of pups from their burrows at approximately 6 weeks of age. Johnson (1927) presented the first account of black-tailed (C. ludovicianus) pups born in captivity, and Anthony and Foreman (1951) provided additional data on growth and development during studies of reproductive physiology of the same species. Tileston and Lechleitner (1966) compared the biology of white-tailed (C. leucurus) and black-tailed (C. ludovicianus) prairie dogs from colonies in Colorado and presented data on seasonal weight changes in adults and pups after emergence. Bakko and Brown (1967) investigated reproductive physiology of white-tailed prairie dogs from Wyoming and also reported on seasonal weight changes of adults and postemergent young. King (1955) studied demography and behavior of black-tailed prairie dogs from colonies in South Dakota and Smith (1958) reported on the natural history of black-tails fror colonies in Kansas. Information on reproduction in white-tailed and Gunnison's prairie dogs also was presented by Stockard (1929), Aldous (1935), Longhurst (1944) and Scheffer (1947). We found no information on the biology of Cynomys mexicanus except for brief mention in systematic accounts (e.g., Hollister, 1916). The first laboratory breeding and subsequent birth of a litter of six C. mexicanus pups is reported herein. Information is provided on growth and development, behavior and vocalizations of adults in the laboratory and the field. Because C. mexicanus may represent a relict population derived from C. ludovicianus (Hoffmann and Jones, 1970), we have compared our data with similar published data for other Cynomys.

Sound Communications of Black-tailed, White-tailed, and Gunnison's Prairie Dogs

The sounds of black-tailed, white-tailed, and Gunnison's prairie dogs were studied in Colorado and Wyoming from February 1964 to June 1966. Observations, photographs, and tape recordings were made in the field and were supplemented by data collected from captive prairie dogs. The sounds of black-tailed prairie dogs were named and had the usual function as follows: ( 1 ) repetitious barks alert; (2) chuckle alert; (3) barks threat; (4) wee-oo contact; (5) snarl threat; (6) growl threat; (7) scream distress; (8) raspy purr pleasure; and (9) tooth chatter threat. The sounds of white-tailed prairie dogs were: (1) repetitious barks alert; (2) chuckle alert; (3) laughing barks contact; (4) snarl threat; (5) growl threat; and (6) scream distress. The sounds of Gunnison's prairie dogs were: (1 ) repetitious barks alert; (2) rapid barks apprehension; (3) chuckle alert; (4) raspy chatter contact; (5) snarl threat; (6) growl threat; (7) scream distress; and (8) tooth chatter threat.

An Epizootic of Plague in Gunnison's Prairie Dogs (Cynomys Gunnisoni) in South‐Central Colorado

In June 1964 and epizootic of plague began in Gunnison's prairie dogs (Cynomys gunnisoni) in Cochetopa Park, Saguache County, Colordo. Seven colonies of prairie dogs were known in the area at that time. By the end of the summer, 2 of these colonies were exterminated and several others were greatly decimated. A residual phase of the epizootic continued through the summer of 1965 and terminated in 1966 leaving only a few prairie dogs in 2 colonies. No evidence was obtained to indicate that the populations of other mammals living in the area wer adversely affected by plague. The mammalian reservoir of plague in this area remains unknown, but the data suggest that small mammals such as the deer mouse (Peromyscus maniculatus) and the golden—mantled ground squirrel (Citellus lateralis) may be involved. The spread of infection from prairie dog to prairie dog is via flea vectors, especially Opisocrostis tuberculatus, O. labis, and Oropsylla idahoensis. The vector responsible for getting the initial infection into the prairie dogs from some reservoir source is unknown. Apparently, the transfer of Pasteurella pestis from a mammalian reservoir into a population or prairie dogs is an improbable event, and this improbability, rather than any resistance to infection, or resistance to disease, by the prairie dogs is a major factor which allows them to live in such areas of plague enzooticity.