A katarn is a predatory quadruped native to the planet Kashyyyk. They have slender bodies with rodent-like tails, and narrow faces leading back to a cartilaginous ridge protecting their neck and shoulders. Their paws have opposable digits, and their lower limbs are covered with sharp spurs, both of which allow them to climb and hang from the branches of the giant wroshyr trees.

Katarns are creatures of great importance in the Wookiee's culture. The Wookiees, who called the Katarn the "Old Prince", hunted them in hrrtayyk ceremony. Wookiees said the katarns were born by a wound to Kashyyyk that fell from the sky ages ago (possibly a Rakatan satellite) and made a home for the Katarn. The katarns then hunted the Wookiees, thus unlocking the Wookiee's "inner fire". To thank the katarn, the Wookiees hunted them. They believe that someday it would be the Katarn's turn to hunt the Wookiees again.

Katarns are ferocious and merciless predators which would track their prey for long periods before choosing an opportune moment to strike. They have been described as "silent, shadowy, and deadly," qualities which made them the mascot of Judder Page's Katarn Commandos.

Some katarns are domesticated as the war-mounts of Wookiee dragon troopers. On another note, there is a small subspecies of katarn that populates the shadowlands. These katarn have no climbing abilities as evidenced by their four large trunk-like legs. They also have two small dangling manipulator arms. They have more rounded out edges than the main katarn species and two large tusks. The reformed Revan battled several of these in his second trip to find the Kashyyyk star map.