Brahmin have been domesticated throughout the years since the Great War. Some brahmin can be seen wandering the Wasteland, but this is rather rare. Through their domestication, they have been used primarily for meat, milk, and their hides which are tanned to make leather. Traders often use them as pack animals.
They attack by head-butting or trying to gore someone with their horns, however in the Mad Brahmins encounter, a group will charge at the Chosen One and explode on impact.
As a result of the constant radiation, these formerly normal cows have sprouted a second independent head. Brahmin have eight stomachs, and male brahmin have four testicles. Their skin has turned a toasty, dusty orange-red color from the fallout exposure and their horns have become a dirty brown. In addition, their udder has increased in size.
Brahmin are low level creatures and can be little more than a nuisance in the beginning of the game, if you can even find one that is hostile. In fact, most brahmin throughout the game are non-hostile and will only attack if provoked, as they are mainly found in ranches and small settlements. When they attack they run and ram into foes, swinging their horns into the body of the threat. Although their hide is thick, bullets will still penetrate and kill them rather quickly.