Bison first came to North America about 200,000 years ago when the Bering land bridge connected Siberia with Alaska. Bison, originally from China, migrated from Russia's steppes to Alaska and on to the Great Plains grasslands. They were one of the few megafauna to survive the Pleistocene era. Recent DNA analysis and fossil dating have allowed evolutionary biologists and paleontologist to trace the migratory and genetic history of bison subspecies before and after the last ice age.  Bison have a symbiotic relationship with grasslands and as grasses followed the melting edge of the last ice age sheets, bison followed. Fossils from Alberta show that the landscape was dominated by horses and mammoths before the last glaciation, and by bison after the ice receded. Featuring: Professor Duane Froese, Dr. Alwynne Beaudoin, and Dr. Chris Jass.