UESP
Modded
Dunmer may train large rats to kill other rats in place of owning cats.
Quote
Back in Cyrodiil, I owned a dog to keep the vermin out of my tavern. But that was before I decided to join the Imperial colonists headed to Vvardenfell. You don’t see many dogs here in Morrowind — or cats for that matter. Apparently the Dark Elves actually domesticated some larger breeds of rats and trained them as ratters. Fascinating, isn’t that? But I have another idea. Maybe something you can help me with.
— Burcanius Varo (dialogue)1