Given that they're the descendents of dinosaurs and so likely learned this practice from their ancestors, would it not make more sense to say we likely learned about divorce from them?
It would be hilarious if ancient birdwatchers were watching dinosaurs through their hand binoculars and suddenly were like, "did you see that love? They were together 20 years and she's just handed him something written on a leaf and chucked him out, I think we'll call this divorce. Let us teach our fellow humans the way of the Tyrannosaurus Rex!"