William Caire and Chris L. Sloan
Biology Department, University of Central Oklahoma, Edmond, OK 73034
Received: 1996 Mar 13; Revised: 1996 Jul 15
The first specimen of woodchuck, Marmota monax, was preserved from eastern Oklahoma 35 years ago (1). Since that time, few specimens have been preserved and almost nothing has been reported about its ecology in Oklahoma. The scarcity of records from Oklahoma make characterization of the range within the state difficult and additional records from outside the presently described range are noteworthy. Caire et al. (1) listed all records known for Oklahoma and suggested the woodchuck was limited in distribution to northeastern portions of the state. Two specimens from Payne County, and one from Kay County, were the only north central Oklahoma records. Two recent sightings suggest a range extension into Oklahoma County 45 km southwest of the closest known record in Payne County.
On 16 March 1995, an adult male woodchuck was found dead on U.S. Highway 66, 6 km east of Edmond, Oklahoma County, by Leon Mixer and Kelly Platt. External measurements were: total length, 649 mm; length of tail, 133 mm; length of hind foot, 89 mm; and length of ear, 29 mm. The surrounding habitat was hilly, with occasional sandstone outcrops and cross timber vegetation composed primarily of post oak and blackjack oak. Wheat fields, pastures, and mixed-grass prairie fragments were in the vicinity.
On 13 May 1995, at 1527 h (sunny; air temperature ca. 30 °C) an adult (sex unknown) woodchuck was observed (C. Sloan) 4.8 km northeast of Arcadia in Oklahoma County, on the Morningside Farms Ranch. Habitat was similar to that described above. The animal emerged from the forest edge, proceeded slowly across a rock wash area, and entered the forest on the opposite side of the wash.
These records of woodchucks in Oklahoma County, and the absence of previous reports from the area, can be interpreted in either of two ways. The records might suggest a recent dispersal into central Oklahoma from northeastern or eastern portions of the range. In this case, it would appear that the Cimarron and Arkansas river systems are not presently effective in blocking dispersal and that woodchucks can exist in the crosstimber oak woodlands of central Oklahoma as well as the deciduous forests of eastern Oklahoma. If the range of woodchucks is increasing in Oklahoma, the aridity and grasslands of the west could block further westward expansion.
Another possible explanation for the presence of Marmota in central Oklahoma is that the woodchucks could have been purchased or captured elsewhere, kept as pets for a period of time, and then released. None of the pet stores contacted in the greater Oklahoma City area had any information regarding woodchucks for sale. However, a local naturalist, Bob Jenni (pers. comm.), recalls a woodchuck having been brought into this area within the last year as a pet, but he had no other information about its present status. Attempts to locate anyone in the area who might have brought the woodchucks into the region have been unsuccessful.
Because the possibility exists that these may have been released animals, we are hesitant about affirming the two sightings as evidence of a range extension. However, if they are indeed representative of a recent expansion of the range of woodchucks in Oklahoma, then it is important to have these events documented in the literature for future comparisons.
1. Caire, W., Tyler, J.D., Glass, B.P. and Mares, M.A., Mammals of Oklahoma. Univ. Oklahoma Press, Norman, OK (1989).