Talk:Rats/@comment-16533050-20180524213822/@comment-26199726-20180525195246

Once summoned an upgraded rat swarm against Howlers, they took out the entire swarm with a single Howling Bolt. So I think it's safe to say yes.

Difficulty recalling it is understandable - the only "large" rat swarms in Dishonored 2 are the ones you summon. But Howling Bolts will be just as effective against the smaller ones, I guess.