Critically Endangered
These may be extinct. They were last seen in 1988, or at least last officially seen. There have been possible sightings since then, and there have been skulls with horns sold in local markets. If there are any left, it is likely there are fewer than 50 adults left in scattered groups which is not a viable number for keeping the population going. It is possible they are still extant in Cambodia, but are extirpated from Thailand and Vietnam. The bulls after the age of 3 can develop this weird shredding of the keratin of their horns, it may be from using their horns to dig. They are almost nocturnal now, possibly as a defense mechanism to avoid humans, their only known predator. Their numbers have diminished because of uncontrolled hunting, especially by the military during wars and other altercations.
I was about 9 when our family did a multiple state trip in our Volkswagen Bus. One of the stops was to a great-aunt and uncle's house, or some distant connection like that. I remember driving the combine in their wheat field, quickly learning that I should probably not drive combines in wheat fields. The other thing I remember was being able to pet a newborn calf, only an hour or so old. I was in a red jumpsuit, quite tacky, but it was the early 1980's, most clothes were tacky. Even though it is a myth that bulls hate red and will charge at it, it isn't a myth that a cranky bull will go after something that is moving erratically, like a 9 year old kid who is really excited to see a still soggy little calf. Thankfully my great uncle or whatever he was noticed that I was attracting entirely too much attention and got me to safety, saving me from getting trampled.