Montana begins its prohibition against consensual adult sexual behavior by defining "deviate sexual relations" as "sexual contact or sexual intercourse between two persons of the same sex or any form of sexual intercourse with an animal."
The Montana statute 45-5-505 Deviate sexual conduct then provides a penalty of not more than ten years imprisonment and a fine of not more than $50,000 upon a successful conviction.
45-5-505 has been found unconstitutional by Gryzcan v. State.