This article is about the Romulan animal. You may be looking for the Romulan engineer, Thrai (Romulan).

The thrai (plural form: thraiin) was the name of a predatory animal that lived on the Rihannsu homeworld, ch'Rihan.

The creature was analogous to the Terran wolverine (gulo gulo); and was possessed of similar legendary traits for persistence, vengeful stubbornness, and ferocity. (TOS - Rihannsu novel: My Enemy, My Ally)