To
find out whether the population has indeed grown, ecological modeler Craig Pease of Vermont Law School and David Mattson, a U.S. Geological Survey (USGS) grizzly field
biologist, looked at 20 years of data on grizzlies tracked with radio collars or spotted by
federal scientists in Yellowstone.
«These are occasional
finds, so you can not do a proper sampling design,» says lead researcher Tomas Hrbek, an evolutionary
biologist at the
Federal University of Amazonas in Manaus, Brazil.