James C. Halfpenny, Ph.D., is a scientist / educator who directs A Naturalist's World, an ecological education company located at the north gate to Yellowstone National Park. A Naturalist's World maintains the Track Education Center which houses over 10,000 footprint casts, photographs, and track accounts. Jim has been tracking for over 50 years and has tracked on all continents. Check out www.tracknature.

com.Meghan Walla-Murphy, B.S. and B.S., is currently an environmental and education consultant based in southern California. She has spent the last seven years delving deeply into tracking, traveling the United States, Africa, Brazil, and China to expand her knowledge base. Meghan also writes natural history articles for several Los Angeles based newspapers.

Elizabeth Rogers, Ph.D., is an ecologist with a life-long interest in the plants and animals of the Great Lakes region. She holds a doctorate in ornithology from Michigan State University and has worked various jobs as an environmental educator, consultant, and as a biologist for a Native American tribe. Tracking is a passion as well as a treasured collaboration she shares with fellow biologist David Tiller. David Tiller, B.S., is a biologist who has resided for 35 years in Michigan's Upper Peninsula.

Retired after 20 years as a environmental consultant with White Water Associates, he continues to work as a free lance biologist. Dave lives in a log home that he built himself. It is situated on 40 acres of land that is adjacent to wild national forest lands. Around his home and elsewhere, David pursues his enduring interest in the birds, mammals, and plants.