I don’t really know the exact difference but I think you’ve gotcher
Cape Buffler in Africa and yer Water Buffler in Asia.
In Americer ya gotcher real buffler which is actually a Bison.
But if you get too close to one you’ll know it’s real! ;^)
As with just about everything in the natural world, it’s actually more complicated than we are aware...
Buffalo (or buffaloe) primarily refers to:
African buffalo or Cape Buffalo (Syncerus caffer)
Bubalus, a genus of bovines including various water buffalo species
Wild water buffalo (Bubalus arnee)
Water buffalo (Bubalus bubalis)
Italian buffalo or Italian Mediterranean buffalo, a breed of water buffalo
Anoa
Tamaraw (Bubalus mindorensis)
Bison
American bison (Bison bison), also commonly referred to as the American buffalo or simply “buffalo” in North America
https://en.wikipedia.org/wiki/Buffalo