Preliminary analysis of familial relationships among gray wolves (Canis lupus) in Yellowstone National Park

Kerry M. Murphy, Douglas W. Smith, Sarah Stevenson, John Varley, Yellowstone Center for Resources, PO Box 621, Yellowstone National Park, WY 82190, USA; Karl Broman, Department of Biostatistics, John Hopkins University, 615 North Wolfe Street, Baltimore, MD 21205-2179, USA; Janet Zeigle, Larry Joe, Genscope, Inc., 850 Lincoln Center Drive, Foster City, CA 94404, USA; Micheal McClelland, 10835 Altman Row, San Diego, CA 92121, USA; Dorris Hafenbradl, Eric Mather, Diversa Corp., 10665 Sorrento Valley Road, San Diego, CA 92121, USA

Maternal and paternal relationships for a reintroduced population of gray wolves in Yellowstone National Park (YNP) were estimated. The objective of the study was to document the breeding system of Yellowstone wolves and compare findings to other recent studies that suggest that gray wolf breeding may deviate from monogomy, the breeding system that is traditionally assumed for wolves.

Genetic data were obtained from blood and tissue samples of the entire set of founding stock of wolves translocated from Canada in 1995 and 1996, and from some of their offspring born subsequently in YNP and vicinity. An exclusion analysis was then applied to allellic data estimated from microsatellite loci. Field-based information on dominance relationships and leadership were collected by observing wolves directly, or indirectly using standard telemetric methods

Genotypes of 89 total wolves (54% of all individuals present) in 10 packs were documented. Preliminary results suggested that Yellowstone wolves were not strictly monogamous. Although females almost always bred with alpha males from within their own packs, three males produced offspring with more than one female in his own pack on at least six occasions. Parents were typically 2 years of age or more, but at least one yearling female produced offspring at about 12 months of age. We believe that abundant prey available to this expanding wolf population may enhance polygynous breeding.

Careful analyses at both levels of causation will give us a fuller appreciation for the multitude of causative pathways that influence the behavior of wolves.