Whether a large rat has halachic drisah status to render prey treifah

Description

The Chasam Sofer rules that a rat has no drisah, since the rule 'from the wolf and above' applies only to naturally predatory species, not merely large animals. Additionally, drisah requires action through the paw/claw, not the mouth, and rats attack by biting. For the practical case of a bird bitten on its head, the skull must be examined for fracture and brain membrane puncture; the earlier ruling to wait twelve months was incorrect.