"I think I am also a donkey. I do not know what happened when I left the bar, but I am seriously in love with (the) donkey," Sunday Moyo told the court, according to The Herald newspaper.
Moyo, 28, was arrested in the town of Zvishavane, about 185 miles south of the capital Harare on Sunday.
He said he had paid $25 for a prostitute, and was surprised Sunday morning when he heard people accusing him of having sex with a donkey.
Moyo has been charged with bestiality and remanded in custody. The court has ordered him to undergo a mental examination, The Herald said.