Iota Geminorum IV was the uninhabited fourth planet in the Iota Geminorum system. This was the homeworld of the tribble. Reptiles were the natural predators of tribbles on this world, and were known to keep the tribble population in check, which when removed to other environments bred uncontrollably. This planet was located within the Klingon sphere of influence.
In 2369, a chart illustrating various creatures, including tribbles, from around the known galaxy was displayed in a classroom aboard Deep Space 9. (TOS: "The Trouble with Tribbles"; DS9: "The Nagus", okudagram; ENT: "The Breach")