Houyhnhnms (usually pronounced "whinnems," as in "whinny") are a race of intelligent horses in Gulliver's Travels. Gulliver encounters them after washing up on their beach. Mistress is their apparent leader, at least in terms of caring for Gulliver. However, while their is a council, there is no class system portrayed in the film; this contrasts with the original text, where Gulliver's "Master" has several servants.
Houyhnhnms contrast strongly with the savage humanoid Yahoos, ever quarrelling and the source of all that is bad in their country. By contrast, the Houyhnhnms have a utopian society, based on reason and respect for each other. When one Houynhnm meets another, both observe a moment of silence before either speaks, so as to carefully consider their words.