Indian Bison or Gaur
Bos gaurus gaurus
This is a mighty beast. Six feet at the shoulder weighing 1000 kilo grams, it needs to fear only three enemies - a mightier bull or a marauding tiger or humans. These are the wild cousins of domesticated cattle but are rather large and avoid humans.
Listed as vulnerable, they face depleting grazing areas and infections from domestic cattle. There were instances when big herds were wiped out from attack of diseases such as foot-and-mouth. Their cousins in the fareast and China are even faring worse and are put on critically endangered list.
This is not the best view of this wonderful animal. He gave me very little time before he disappeared into the woods. I was watching his mate when this big fellow suddenly came into view and unnerved me. Of course, they were captive and I was behind the concrete barricade but still it was an awesome sight seeing him so close.
I had seen one in the wild few years ago but even then he did not give me a chance to set the camera. I was using an SLR film camera and driving the car and I had no chance. For such massive animals, they are so fast and vanish in a jiffy.
EDIT: Happened to see one in the wild recently. You can see it here.