§ III. On Bestiality

The unspeakable and execrable crime of bestiality is sexual intercourse with a beast.

I say 1st. Bestiality is the gravest among the sins of lust, both because to be mixed with a beast is most repugnant to rational nature, and because it was punished most gravely in the old law; for it is said, Exod. xxii, 19: "Whoever has intercourse with a draught animal or herd-animal, let him die by death; kill the beast also." Indeed that sin is more horrible than sodomy itself, because to approach a different species departs still more from right order than to approach an undue sex or vessel. - Cf. St. Alphonsus, n. 474.

I say 2nd. Impure touches with beasts, although they are not sins of bestiality properly so called, nevertheless are to be declared when some venereal pleasure is sought from them. But the circumstance does not seem necessarily to be declared if someone, by means of the tongue of a herd-animal or another beast, excites venereal pleasure or pollution in himself. Nor is it necessary to explain in confession of what species the beast was, nor whether it was male or female. - Cf. St. Alphonsus, n. 474.