James,
I work in the technology investment business and have experince with a couple of the leading RFID companies. RFID is really meant for close range use. It isn't the sort of thing used for wildlife.
However the gentleman that has guided me twice on amazing Grizzly bear tours in Katmai Alaska is a world known bear researcher, Chris Morgan.
Chris is also involved with the tagging of cougars in the northwest. His contact info is

Chris Morgan (M.S. Ecology)
Co-Director/Bear Specialist
Grizzly Bear Outreach Project (GBOP)
PO Box 28656, Bellingham
Washington State 98228-0656, USA
Tel: (+1) 360 734 6060
Fax: (+1) 360 734 0800
email: chrismorgan@insightwildlife.com

Grizzly Bear Outreach Project web site: http://www.bearinfo.org

Promoting an accurate understanding of grizzly bears and their recovery in the North Cascades Ecosystem through community education and involvement

ALERT! Read about the new GBOP Bear Smart Program:
http://www.bearinfo.org/bearsmart.htm