Brillas are herbivores, usually grazers but adaptable enough to browse or forage for fruits and tubers. They have a lipped beak, as well as some small cheek pouches. They have long necks, which they can use to collect food, look around and move the head far enough so the arms can easily clean the scrafs. They rely largely on sight, although they have good senses of hearing and smell. They have a long tail that can flick in most directions quickly, to keep balance. Their hoof-like feet have folds of skin on the lower regions. This is believed to help prevent parasites from climbing up the legs to the body.
These animals have short, densely-haired arms which are used as spare balance-detectors, scraf-cleaners and as wind detectors. The long, wide hairs on the brilla are used for sensory input, usually about the wind but that can also feel vibrations from the air, acting as back-up ears. This enables it to make split-second adjustments to enable it to run extremely fast in a bipedal stance. They evolved to run at fourty miles an hour in cluttered forest environments for long distances, and in an open environment, these animals can run at 80 miles an hour for 15 minutes. They also have a low centre of gravity, as the bone in the upper body is hollow and sandless, while the legs are heavier. They have powerful lungs and a just-as-strong heart that take up much of the body space. They need to run this fast because the local predators hunt in packs and can attack from a distance, so the quickest escape possible is needed before they are in range and trapped.
Brillas live in family herds. A male and female dominate the herd, with their daughters mating with lone males who then join the herd. They look after their young, to an extent. The young are protected and nurtured, but they have to do foraging themselves. Some brillas have been domesticated by Irkapuths, who use them as a means of high-speed transportation. They are ridden by the rider Irkaputh leaning on the arms to change direction, pressing down hairs in front to slow down, and moving hairs in front outwards to speed up. A small family of Irkapuths can travel 20 miles in fifteen minutes in this way, as long as their animal is healthy and obidient.