Albert Fish , Peter Kurten  Dabblers have transitory opportunistic sexual relations with corpses, but this is not their preference. Category F homicidal necrophiles commit postmortem sex acts only while in a catathymic state.
Exclusive mutilophiles derive pleasure purely from mutilating the corpse, while sexual cannibals and vampires are sexually aroused by eating human body parts. Category A, C, and F offenders may also cannibalize or drink the blood of their victims.
The sample was divided into genuine necrophiles, who had a persistent attraction to corpses, and pseudo-necrophiles, who acted out of opportunity, sadism, or transient interest.
The researchers theorized that either of the following situations could be antecedents to necrophilia: They develop an exciting fantasy of sex with a corpse, sometimes after exposure to a corpse. The authors reported that, of their sample of genuine necrophiles: IQ data was limited, but not abnormally low.
Rosman and Resnick concluded that their data challenged the conventional view of necrophiles as generally psychotic, mentally deficient, or unable to obtain a consenting partner. Non-reproductive sexual behavior in animals Necrophilia has been observed in mammals, birds, reptiles and frogs.
The label is still used for necrophilia in animals. Kees Moeliker made one observation while he was sitting in his office at the Natural History Museum Rotterdam , when he heard the distinctive thud of a bird hitting the glass facade of the building. Upon inspection, he discovered a drake male mallard lying dead outside the building. Next to the downed bird there was a second drake mallard standing close by.
As Moeliker observed the couple, the living drake pecked at the corpse of the dead one for a few minutes then mounted the corpse and began copulating with it. The act of necrophilia lasted for about 75 minutes, in which time, according to Moeliker, the living drake took two short breaks before resuming with copulating behavior.
Moeliker surmised that at the time of the collision with the window the two mallards were engaged in a common pattern in duck behavior called "attempted rape flight". The sea lion nudged the seal repeatedly, then mounted her and made several pelvic thrusts.
Approximately ten minutes later, the sea lion became disturbed by the researcher's presence, dragged the corpse of the seal into the water and swam away while holding it. Several months later, the same sea otter was again observed copulating with the carcass of a different female. In each of six trials, individuals from flocks of were observed attempting to copulate with the dead sand martins.
This occurred one to two months after the breeding season; since copulation outside the breeding season is uncommon among birds, the researcher speculated that the lack of resistance by the corpses stimulated the behavior.
He commented, "This isn't the first time I've seen cliff swallows do this; the bright orange rump sticking up seems to be all the stimulus these birds need. In one, the partner of a male lizard got caught in fencing wire and died.
The male continued to display courtship behavior towards his partner two days after her death. This lizard's necrophilia was believed to stem from its strong monogamous bond. On the first day, the corpse was freshly dead, but by the second day it was bloating and emitting a strong putrefying odor. The researcher attributed the behavior to sex pheromones still acting on the carcass.
An Unnatural History shows a male toad copulating with a female toad that had been run over by a car. It goes on to do this for eight hours. If the mounted object is a live frog not appropriate for mating, it will vibrate its body or vocalize a call to be released. Dead frogs cannot do this, so they may be held for hours.