Zoophilia

Zoophilia is a paraphilia involving a sexual fixation on non-human animals. Bestiality is cross-species sexual activity between humans and non-human animals. The terms are often used interchangeably, but some researchers make a distinction between the attraction (zoophilia) and the act (bestiality).[1]

Roman oil lamp depicting a zoophilic act, 1st–3rd century A.D.

In most countries, bestiality is illegal under animal abuse laws or laws dealing with buggery or crimes against nature.