...yeah, a gaur's a type of cow.
Gaur (Bos gaurus) are a relative of the domestic cow. They are found in India and South-Southeast Asia, including China, Vietnam, India and Indonesia. They are not as closely related as the aurochs are to modern cattle - it's more like the relationship between a dog and a coyote. Before you ask, yes, the two can interbreed.
Gaur are giant cattle. They are bigger than any known bovine species, living or dead. They can reach up to 10 feet long and 7 feet high; the aurochs only reached 6.6 feet at the shoulder. Males are larger than females. Only elephants, rhinoceroses, and hippos are larger than the gaur.
Unlike domestic cattle, gaur have very few natural predators. The young can be picked off by leopards and dholes (sort of like Asian wolves), but nobody messes with the adults. A healthy adult gaur was once reported killing a tiger - big cat, the king of beasts in China - that had been stupid enough to mess with it during the daytime. (During the night, it's still a bit hard - a fight between the two is actually a really close match, no matter WHAT tiger fans tell you.) No wonder the Hindus treat cows nicely; the gaur give them a very good reason to see cows as friends, not food.
Just put down the burger and nobody gets hurt...
Alas, gaur are becoming vulnerable. It's not because humans are being stupid and killing off all the gaur for sport; they're far too awesome for that. Instead, the gaur's food sources are becoming scarcer and scarcer.
By the way, the bull on the original Red Bull bottle was a gaur, not Bos taurus. This does not make that sugary crap any better for you; nobody really knows what taurine does, but it was first extracted from bull bile. This is one of those things that makes you wonder how people found out, but at the same time, you don't wanna know.
Red Bull: It's really bile!