Nephroblastomas seem to be very rare in animals with mesonephritic kidneys (fishes and amphibia), although immense numbers of many species are kept as pets and in laboratories. A single case was recorded in the steelhead trout (5). The steelhead trout (Salmo gairdneri, Rich.) is the same species as the rainbow trout, differing only in that it spends part of its life in the sea and returns to fr...

Variation in vital demographic (e.g., survival) rates of males can influence population dynamics, but the male segment of the population is frequently ignored in ecological studies of mammals. Using a multistate capture– mark–recapture model and 44 years (1962–2006) of data from 17 habitat patches, we investigated spatial and temporal variation in age-specific survival rates of male yellow-bell...

Social behaviour was proposed as a density-dependent intrinsic mechanism that could regulate an animal population by affecting reproduction and dispersal. Populations of the polygynous yellow-bellied marmot (Marmota flaviventris) fluctuate widely from year to year primarily driven by the number of weaned young. The temporal variation in projected population growth rate was driven mainly by chan...

I implanted radio transmitters in 183 yellow-bellied marmots (Marmota flaviventris); transmitters were replaced <6 times in 73 animals, for 300 surgeries. Surgical procedures were simple, effective, and largely trouble-free. Survival 30 days later was >98%, and growth rates (21 g/day) were the same for animals with or without implants. Pregnancy rate (0.52 litters/yr) and mean litter size (4.3)...

Home range is the area that marmots use to obtain food and burrows necessary for growth, reproduction and survival. During regular censuses, the position of each marmot was recorded as a pair of coordinates from a calibrated grid overlain on a photograph of the colony site. Home range area was calculated as the product of the area of a grid square multiplied by the number of grid squares a marm...

Department of Ecology and Evolutionary Biology, University of California, Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA (AM-C, DTB) School of Biological Sciences, University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ, United Kingdom (JGAM) Ecology & Evolutionary Biology Department, The University of Kansas, 1200 Sunnyside Avenue, Lawrence, KS 66045-7534, ...

The possession of a suitable spot on the wintering grounds may be important for an individual's survival in migrant species showing territoriality in the nonbreeding season (e.g., Rappole et al. 1989, Winker et al. 1990). If the earliest arrivals are favored in securing the best winter territories (e.g., Smallwood 1988), then selection might favor individuals who quickly return to wintering are...

Immigration and recruitment were examined in six colonies of Yellow-bellied Marmots (Marmota flaviventris) for 220 colony-years. Recruitment occurred significantly more often than immigration. Rates of immigration and recruitment were not significantly correlated among colonies nor were either significantly related to the area of the colony. The rates of immigration and recruitment did not diff...