Buffalo once roamed the grasslands of North America in huge herds, numbering in the tens or hundreds of thousands each. But commercial hunting in the 19th century reduced their numbers to around 500 in total — it’s only been in the past few decades that their population has recovered to any extent.
The struggle now is sorting out which buffalo are really pure buffalo, vs. which ones have a significant number of genes from domestic cattle.
By the way, buffalo are known to have tempers, and are wild animals at any rate — so you don’t want to approach them for a good shot. I took the above video from roadside; while taking pictures, a part of the herd decided to wander over toward me. I got in our car a few seconds after wrapping up this clip.