Dharmaguptaka-vinaya 1.18

1.18

爾時有一乞食比丘依林中住，有一雌獼猴先在彼林中。時乞食比丘到村乞食還在林中食，食已餘食與此獼猴，如是漸漸調順，逐比丘後行乃至手捉不去。此比丘即捉獼猴共行不淨。時有眾多比丘案行住處，次至彼林中。時彼獼猴在比丘前，迴身背之現其婬相。時諸比丘作是念：「此獼猴在我等前迴身現其婬相，將無與餘比丘作不淨行耶？」咸共相告在屏處伺之。彼比丘乞食還在林中，食已以餘食與彼獼猴，獼猴食已便共行不淨行。諸比丘見已即來語言：「如來不制言：『比丘不得行不淨行耶！』」彼比丘報言：「如來所制男犯婦女，不制畜生。」諸比丘聞此語已往至佛所，頭面作禮以此因緣具白世尊。世尊爾時以此因緣即集比丘僧，無數方便呵責彼乞食比丘言：「云何，比丘！與獼猴共行不淨行耶？初入波羅夷。欲說戒者當如是說：若比丘共比丘同戒，若不還戒、戒羸不自悔，犯不淨行乃至共畜生，是比丘波羅夷不共住。」

At that time, there was an alms-seeking bhikṣu who lived in dependence on a forest, where a female monkey had previously resided. The alms-seeking bhikṣu went to the village to beg for food and returned to the forest to eat. Having eaten, he gave the leftover food to this monkey. In this manner, she gradually became tame, following behind the bhikṣu and not running away even when held by hand. This bhikṣu then took hold of the monkey and engaged in unchaste conduct with her. At that time, many bhikṣus were inspecting dwelling places and came in turn to that forest. At that time, that monkey turned her back before the bhikṣus and displayed lustful behavior. Then those bhikṣus thought: "This monkey turned around before us and displayed lustful behavior; could it be that she engaged in unchaste conduct with some bhikṣu?" They informed one another and waited in a secluded place to observe. That bhikṣu returned to the forest from begging for food; having eaten, he gave the leftover food to that monkey. After the monkey had eaten, they engaged in unchaste conduct together. Seeing this, the bhikṣus came forward and said: "Did the Tathāgata not lay down the rule, saying, 'A bhikṣu must not engage in unchaste conduct'?" That bhikṣu replied: "What the Tathāgata laid down applies to a male violating a woman; he did not lay down a prohibition regarding animals." Having heard these words, the bhikṣus went to the Buddha's place, bowed their heads and faces, and reported this matter in full to the Bhagavat. At that time, on this account, the Bhagavat assembled the bhikṣu-saṅgha and rebuked that alms-seeking bhikṣu with countless skillful means, saying: "How could you, bhikṣu, engage in unchaste conduct with a monkey? From the initial entry, it is a pārājika. When one wishes to recite the precepts, one should recite them thus: 'If a bhikṣu shares the same precepts with the bhikṣus, and without having renounced the precepts, or with his precepts weakened and without confessing of himself, commits unchaste conduct, down to doing so with an animal, that bhikṣu is defeated (pārājika) and may not dwell together [with the saṅgha].'"