The terms are often used interchangeably, but some researchers make a distinction between the attraction (zoophilia) and the act (bestiality).
Three key terms commonly used in regards to the subject — zoophilia, bestiality, and zoosexuality — are often used somewhat interchangeably.
Zoosadism specifically is one member of the Macdonald triad of precursors to sociopathic behavior.
which he defined as a sexual attraction to animal skin or fur.
Martin Duberman has written that it is difficult to get a random sample in sexual research, and that even when Paul Gebhard, Kinsey's research successor, removed prison samples from the figures, he found the figures were not significantly changed.
By 1974, the farm population in the USA had declined by 80 percent compared with 1940, reducing the opportunity to live with animals; Hunt's 1974 study suggests that these demographic changes led to a significant change in reported occurrences of bestiality.
Sexual fantasies about zoophilic acts can occur in people who do not have any wish to experience them in real life.
Nancy Friday notes that zoophilia as a fantasy may provide an escape from cultural expectations, restrictions, and judgements in regard to sex.
Confusing the matter yet further, writing in 1962, Masters used the term bestialist specifically in his discussion of zoosadism.
Stephanie La Farge, an assistant professor of psychiatry at the New Jersey Medical School, and Director of Counseling at the ASPCA, writes that two groups can be distinguished: bestialists, who rape or abuse animals, and zoophiles, who form an emotional and sexual attachment to animals. Williams and Martin Weinberg studied self-defined zoophiles via the internet and reported them as understanding the term zoophilia to involve concern for the animal's welfare, pleasure, and consent, as distinct from the self-labelled zoophiles' concept of "bestialists", whom the zoophiles in their study defined as focused on their own gratification.
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 percentage of males who reported sexual interactions with animals in 1974 was 4.9% (1948: 8.3%), and in females in 1974 was 1.9% (1953: 3.6%).