Lluma were large in size, with four long, knobblly legs with four-toed feet, and a long curved neck, as well as a short tail. They had slimy gray-brown hides and two lines of green biolumiescent spots that crossed the length of their necks. They were herbivorous and grazed mainly on a variety of different types of fungi. They were herd animals and lived in groups of at least twenty, although herds as large as two-hundred individuals existed, primarily in the equatorial regions of the planet Nyriaan.
Lluma were hermaphroditic and an individual could assume one of three genders: male, female and neutral; depending upon the season and the composition of a herd. Typically, about 20% of the individuals in a given herd were female and 80% were neutral, with one single bull, who mated with the females. The purpose of the neutral lluma was not entirely clear, but they seemed to fulfill a protective role, by surrounding the males and females while the herd traveled.
Nyriaan was subjected to violent storms and the lluma seemed to have had some form of reliance on these tempests, which brought the species to the interest of biologists. Lluma herds would often follow the paths of past storms and would sometimes change direction when their route intersected the path of another such tempest. It was believed by scientists that research into lluma behaviour might reveal clues for helping to predict future storms.
Lluma were sometimes preyed upon by chlovi cats, the top predator in the Nyriaan food-chain. They were also considered by Nyriaans various groups of colonists and settlers to taste delicious, which resulted in some of the smaller lluma herds being hunted to death.