Soṇasutta
“Pañcime, bhikkhave, porāṇā brāhmaṇadhammā etarahi sunakhesu sandissanti, no brāhmaṇesu. Katame pañca? Pubbe sudaṁ, bhikkhave, brāhmaṇā brāhmaṇiṁyeva gacchanti, no abrāhmaṇiṁ. Etarahi, bhikkhave, brāhmaṇā brāhmaṇimpi gacchanti, abrāhmaṇimpi gacchanti. Etarahi, bhikkhave, sunakhā sunakhiṁyeva gacchanti, no asunakhiṁ. Ayaṁ, bhikkhave, paṭhamo porāṇo brāhmaṇadhammo etarahi sunakhesu sandissati, no brāhmaṇesu.
Hounds
“Mendicants, these five traditional principles of the brahmins are exhibited these days among hounds, but not among brahmins. What five? In the past brahmins had sex only with brahmin women, not with others. These days brahmins have sex with both brahmin women and others. But these days hounds have sex only with female hounds, not with other species. This is the first ancient principle of the brahmins exhibited these days among hounds, but not among brahmins.