Thrai

The Thrai (plural form: thraiin) is the name of a predatory animal that lives on the Rihannsu homeworld of ch'Rihan.

The creature is analogous to the Terran wolverine Gulo lusscus; and is possessed of similar legendary traits for persistence, vengeful stubbornness, and ferocity.

(TOS novel: Rihannsu: The Bloodwing Voyages - My Enemy, My Ally)