What is "winter count"

Winter counts ( Lakota: waníyetu wówapi or waníyetu iyáwapi) are pictorial calendars or histories in which tribal records and events were recorded by Native Americans in North America. The Blackfeet, Mandan, Kiowa, Lakota, and other Plains tribes used winter counts extensively. There are approximately one hundred winter counts in existence, but many of these are duplicates.