The Academy of Natural Sciences, Thomas Jefferson Fossil Collection, Philadelphia, PA, (See: species Equus scotti ) Others died out at the end of the last ice age with other megafauna. ^ ""Native Americans: The First Farmers." ''AgExporter'' October 1, 1999" . Allbusiness.com . http://www.allbusiness.com/agriculture-forestry-fishing-hunting/331083-1.html . Retrieved 2010-05-23 .   ^ Spooner, DM;