The Tarasins are a bipedal, sapient reptilian species indigenous to Cularin. They are remotely related to the gigantic kilassin.
Tarasins are 1.6 to 1.7 meter - tall reptilians covered in translucent scales that allow the species' color-changing skin below to show through. Tarasins also have a colorful fan of flesh and scales—known as a kampo— that opens around their heads when they experience strong emotional distress, which could be a detriment to negotiations, as it is difficult for a Tarasin to hide discomfort. This color-changing ability is useful for camouflage and communication, and the scales naturally repelled heat. Some examples of colors they take on includes being brown when calm and in a comfortable environment, or becoming red after extended exertion or when excited. Tarasin also have short tails and short spines that protrude from their forearms — known as a sa'tosin — which give the creatures the ability to sense the use of the Force. Tarasins are naturally curious and protective but also slow to anger. What they lack in sheer physical strength they make up for with a brilliant intellect.
Although the Tarasins initially lived in nomadic tribes, at some point in their past they decided to create a different society. Tarasins since lived in a tribal system in the jungle underbrush of Cularin, grouping together in clans called irstat. Most irstat number several dozen, but they can be much bigger.
The "alien" cities of Gadrin and Hedrett have a minority Tarasin population.

The buildings of an irstat are made of wood, and to outsiders looked like they could be broken down and moved easily, but the Tarasin are not normally nomadic anymore. The eldest female of each tribe is revered as the "Mother", and regarded as an exemplar of perfection. She serves as the spiritual leader of the irstat. The second eldest female filled the role of chief, called the Irstat-Kes. Females are not seen as superior, but this situation was seen as practical, as the males are away from the irstat much of the time gathering food and other resources.

The Tarasin believe they have a symbiotic relationship with Cularin, and their religion is based around the appreciation of the natural world. This closeness with their homeworld is what makes the Tarasin reluctant to leave it for an extended time. The Tarasin have a strong connection with the Force, and their spiritual leaders were often able to call upon the Force in small ways. When the Almas Academy was established, a number of Tarasin studied there to become Jedi.

The Tarasin believed that the ch'hala tree is sacred (and in particular the Sacred Ch'hala Tree Grove). This may have been influenced by the trees having a similar ability to shift their colors as the Tarasin, but it is also the most unique tree on Cularin. As part of the Cularin Compact, the Tarasin did allow a few of these trees to be harvested each year, but only as live transplants.

Tarasins are normally vegetarians, though they hunt kilassin for other uses, such as for their skins or medicinal uses, as they find it distasteful to hunt kilassin for food. Those who live near non-native settlements might take up the eating of meat, but only when around offworlders, and never the meat of kilassin.