Quotation for Kiddushin 163:18

We do not suspect Jewish men of lying with another man or with beasts. Therefore, we do not prohibit them from being alone with them, and if one wants to distance themselves from men or beasts, it is a praiseworthy thing. For the great sages (of old) used to keep beasts at a distance in order that they would not be alone with them. But in these generations because such corrupt people exist one should (therefore) try not be alone with a man.