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

Although sex with animals is not outlawed in some countries, in most countries, bestiality is illegal under animal abuse laws or laws dealing with buggery or crimes against nature.

The Cleveland steamer is a colloquial term for a form of coprophilia, where someone defecates on their partner's chest.

The term received news attention through its use in a U.S. Congress staff hoax email and being addressed by the United States Federal Communications Commission.

Coprophilia (from Greek "κόπρος, kópros—excrement" and "φιλία, philía—liking, fondness"), also called scatophilia or scat (Greek: "σκατά, skatá-feces"), is the paraphilia involving sexual arousal and pleasure from feces. In the "Diagnostic and Statistical Manual of Mental Disorders" (DSM), published by the American Psychiatric Association, it is classified under 302.89 – Paraphilia NOS (Not Otherwise Specified) and has no diagnostic criteria other than a general statement about paraphilias that says "the diagnosis is made if the behavior, sexual urges, or fantasies cause clinically significant distress or impairment in social, occupational, or other important areas of functioning". Furthermore, the DSM-IV-TR notes, "Fantasies, behaviors, or objects are paraphilic only when they lead to clinically significant distress or impairment (e.g. are obligatory, result in sexual dysfunction, require participation of nonconsenting individuals, lead to legal complications, interfere with social relationships)".

Although there may be no connection between coprophilia and sadomasochism (SM), the limited data on the former comes from studies of the latter. A study of 164 males in Finland from two SM clubs found that 18.2% had engaged in coprophilia; 3% as a sadist, 6.1% as a masochist, and 9.1% as both. 18% of heterosexuals and 17% of homosexuals in the study pool had tried coprophilia, showing no statistically significant difference between heterosexuals and homosexuals. In a separate article analyzing 12 men who engaged in bestiality, an additional analysis of an 11-man subgroup revealed that 6 had engaged in coprophilic behavior, compared with only 1 in the matched control group consisting of 12 SM-oriented males who did not engage in bestiality.

Three key terms commonly used in regards to the subject — "zoophilia", "bestiality", and "zoosexuality" — are often used somewhat interchangeably. Some researchers distinguish between zoophilia (as a persistent sexual interest in animals) and bestiality (as sexual acts with animals), because bestiality is often not driven by a sexual preference for animals. Some studies have found that a preference for animals is rare among people who engage in sexual contact with animals. Furthermore, some zoophiles report that they have never had sexual contact with an animal. People with zoophilia are known as "zoophiles", though also sometimes as "zoosexuals", or even very simply "zoos". Zooerasty, sodomy, and zooerastia are other terms closely related to the subject but are less synonymous with the former terms, and are seldom used. "Bestiosexuality" was discussed briefly by Allen (1979), but never became widely established. Ernest Bornemann (1990, cited by Rosenbauer, 1997) coined the separate term "zoosadism" for those who derive pleasure – sexual or otherwise – from inflicting pain on animals. Zoosadism specifically is one member of the Macdonald triad of precursors to sociopathic behavior.

Orf is an exanthemous disease caused by a parapox virus and occurring primarily in sheep and goats. It is also known as contagious pustular dermatitis, infectious labial dermatitis, ecthyma contagiosum, thistle disease and scabby mouth. "Orf virus" is zoonotic—it can also infect humans.

Primarily, orf is a disease of sheep and goats although it has been reported as a natural disease in the following: humans, steenbok and alpacas, chamois and thar, reindeer, musk ox, dog, cat, mountain goat, bighorn sheep, dall sheep, and the red squirrel .