body weight around 3 months. Kits generally stay in the company of their mother through the end of their first summer, and most disperse in the fall. The timing of juvenile dispersal is not consistent throughout American marten's distribution, ranging from early August to October. In south-central Yukon, young-of-the-year dispersed from mid-July to mid-September, coinciding with the onset of female estrus. Observations from Yukon suggest that juveniles may disperse in early spring. Food habits American marten are opportunistic predators, influenced by local and seasonal abundance and availability of potential prey. They require about 80 cal/day while at rest, the equivalent of about 3 voles (Microtus, Myodes, and Phenacomys spp.). Voles dominate diets throughout the American marten's geographic range, though larger prey—particularly snowshoe hares—may be important, particularly in winter. Red-backed voles (Myodes spp.) are generally taken in proportion to their availability, while meadow voles (Microtus''' spp.) are taken in excess of their availability in most areas. Deer mice (Peromyscus maniculatus) and shrews (Soricidae) are generally eaten less than expected, but may be important food items in areas lacking alternative prey species. American marten diet may shift seasonallySimon, Terri Lee. (1980). An ecological study of the marten in the Tahoe National Forest, California. Sacramento, CA: California State University. Thesis or annually. Generally, diet is more diverse in summer than winter, with summer diets containing more fruit, vegetation, and insects. Diet is generally more diverse with the American marten's distribution compared to Pacific marten's, though there is high diversity in the Pacific states. American marten exhibit the least diet diversity in the subarctic, though diversity may also be low in areas where the diet is dominated by large prey species (e.g., snowshoe hares or red squirrels). American marten may be important seed dispersers; seeds generally pass through the animal intact, and seeds are likely germinable. One study from Chichagof Island, southeast Alaska, found that Alaska blueberry (Vaccinium alaskensis) and oval leaf huckleberry (V. ovalifolium) seeds had higher germination rates after passing through the gut of American marten compared to seeds that dropped from the parent plant. Analyses of American marten movement and seed passage rates suggested that American marten could disperse seeds long distances: 54% of the distances analyzed were >0.3-mile (0.5 km). Mortality Life span American marten in captivity may live for 15 years. The oldest individual documented in the wild was 14.5 years old. Survival rates vary by geographic region, exposure