Des Moines University - Department of Anatomy, University of Alaska Fairbanks - Alaska Stable Isotope Facility, University of Alaska Fairbanks - Water and Environmental Research Center, University of Alaska Fairbanks - Alaska Stable Isotope Facility, University of Ottawa - A.E. Lalonde AMS Laboratory, Alpine Veterinary Medical Center, University of California, Santa Cruz - Department of Ecology and Evolutionary Biology, University of California, Santa Cruz - Department of Ecology and Evolutionary Biology, Government of Yukon - Yukon Palaeontology Program, Government of Yukon - Yukon Palaeontology Program and Government of Yukon - Yukon Palaeontology Program