It's always been my opinion that water buff are to cape buff what jaguars are to leopard. Long removed by eons of time and separation to evolve into a bit different animal that matches up with a much wetter environment. Scientist now say that the polar bear has evolved from the grizzily bear through separation and time to survive an artic-marine environment.
These are not the WILD Indian water buffalo, not by the shape of their horns. I'm sure Nakihunter will provide more info. By the shape of their horns, they look like many breeds of typically domesticated water buff, which do spend time in water