18, February 2011) states that sexual contact with animals is almost never a clinically significant problem by itself; it also states that there are several kinds of zoophiles:

Additionally, zoophiles in categories 2, 3, and 8 (romantic zoophiles, zoophilic fantasizers, and regular zoophiles) are the most common, while zoophiles found in categories 6 and 7 (sadistic bestials and opportunistic zoophiles) are the least common.Zoophilia may reflect childhood experimentation, sexual abuse or lack of other avenues of sexual expression. Exclusive desire for animals rather than humans is considered a rare paraphilia, and sufferers often have other paraphilias with which they present. Zoophiles will not usually seek help for their condition, and so do not come to the attention of psychiatrists for zoophilia itself.The first detailed studies of zoophilia date from prior to 1910. Peer reviewed research into zoophilia in its own right started around 1960. However, a number of the most oft-quoted studies, such as Miletski, were not published in peer-reviewed journals. There have been several significant modern books, from Masters (1962) to Beetz (2002); their research arrived at the following conclusions:

Most zoophiles have (or have also had) long term human relationships as well or at the same time as zoosexual ones, and that zoosexual partners are usually dogs and/or horses (Masters, Miletski, Beetz)
Zoophiles emotions and care for animals can be real, relational, authentic and (within animals abilities) reciprocal, and not just a substitute or means of expression. Beetz believes zoophilia is not an inclination which is chosen.
Masters said that since pre-historic man is prehistoric it goes without saying that we know little of his sexual behaviour; depictions in cave paintings may only show the artists subjective preoccupations or thoughts. Pindar, Herodotus, and Plutarch claimed the Egyptians engaged in ritual congress with goats. Such claims about other cultures do not necessarily reflect anything about which the author had evidence, but may be a form of propaganda or xenophobia, similar to blood libel.Bestiality has been accepted in a few North American and Middle Eastern indigenous cultures.Several cultures built temples (Khajuraho, India) or other structures (Sagaholm, barrow, Sweden) with zoophilic carvings on the exterior, however at Khajuraho, these depictions are not on the interior, perhaps depicting that these are things that belong to the profane world rather than the spiritual world, and thus are to be left outside.In the Church-oriented culture of the Middle Ages, zoophilic activity was met with execution, typically burning, and death to the animals involved either the same way or by hanging, as "both a violation of Biblical edicts and a degradation of man as a spiritual being rather than one that is purely animal and carnal". Some witches were accused of having congress with the devil in the form of an animal. As with all accusations and confessions extracted under torture in the witch trials in Early Modern Europe, their validity cannot be ascertained.