Electronic Theses and Dissertations




John R. Hisey



Date of Award


Document Type


Degree Name

Doctor of Philosophy



Committee Chair

Michael L. Kennedy

Committee Member

Melvin L. Beck

Committee Member

Bill A. Simco

Committee Member

Takuya Nakazato


Population features and genetic structure of raccoons (Procyon lotor) and many other solitary-mammalian species are relatively unknown. To better understand these characteristics in P. lotor, microsatellite data collected at local, area, and transcontinental scales and 14 years of local mark-recapture data were used to assess the temporal and spatial extent of philopatry, dispersal, formation of lineages, and genetic patterns associated with these factors. Specifically, I tested the following predictions for raccoons: (1) long-term residency is common; (2) patterns of genetic variation are associated with isolation by distance; (3) closely related animals remain spatially clustered. Only 26 of 215 P. lotor were captured over 2-10 years to become long-term residents, and just 1 juvenile remained philopatric for more than 1 year. Lower proportions of juveniles than other ages and of males than females became long-term residents. Most long-term residencies were established during periodic 2-year peaks in precipitation. The prediction that long-term residents would be common was not supported, and the observed pattern of genetic variability would not facilitate lineage-structuring in the population. Genetic differentiation between sites appeared to be increased through: (1) isolation by distance at local, area, and transcontinental scales; (2) females remaining on local sites; and (3) landscape barriers to movement that could also reduce the spread of diseases by raccoons. Evidence in 22 individuals suggested movement between sites 75-1200 km apart. The prediction that patterns of genetic variation are associated with isolation by distance was supported. The distance between full sibs in 71 pairs inferred by genotypes from microsatellites was <1 km for 46 pairs and >69 km for 5 pairs, with a mean of 7.0 km. Rarely, did sib groups shift locations together, comprise more than 3 individuals, or remain intact in the same vicinity for more than a year. The spatial dispersion among related raccoons was greater in males than in females, in older adults than in younger adults, and during dry years than during wet years. These patterns could speed the spread of key diseases but did not support the prediction that closely related raccoons would remain geographically clustered over multiple years.


Data is provided by the student.

Library Comment

dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.