“Fox (Vulpes Vulpes) Involvement Identified in a Series of Cat Carcass Mutilations”, 2021-12-06 (; similar):
This study was designed to identify the cause of mutilation and death in 32 cats, part of a larger cohort found dead in Greater London, the United Kingdom, 2016–22018. At the time, discussion in the media led to concerns of a human serial cat killer (dubbed The Croydon Cat Killer) pursuing domestic cats, causing a state of disquietude. Given the link between animal abuse and domestic violence, human intervention had to be ruled out.
Using a combination of DNA testing, computed tomography imaging, and postmortem examination, no evidence was found to support any human involvement. Instead, a large association between cat carcass mutilation and the presence of fox DNA was demonstrated (19⁄20). Gross examination identified shared characteristics including the pattern of mutilation, level of limb or vertebral disarticulation, wet fur, wound edges with shortened fur, and smooth or irregular contours, and marks in the skin, muscle, and bone consistent with damage from carnivore teeth. Together these findings supported the theory that the cause of mutilation was postmortem scavenging by red foxes (Vulpes vulpes).
The probable cause of death was established in 26⁄32 (81%) carcasses: 10 were predated, 8 died from cardiorespiratory failure, 6 from blunt force trauma, one from ethylene glycol toxicity, and another from liver failure. In 6 carcasses a cause of death was not established due to autolysis and/or extensive mutilation.
In summary, this study highlights the value of a multidisciplinary approach to fully investigate cases of suspected human-inflicted mutilation of animals.
[Keywords: Felis catus, forensic pathology, mutilation, postmortem examination, scavenging patterns, predation, veterinary forensics, DNA analysis, Vulpes vulpes]
…This raises the question regarding predatory behavior, and whether foxes have always preyed on cats or changes in population densities of cats and foxes in urban areas or food availability have led to predatory behavior. In our study, all those predated were kittens or juveniles, which suggests small size or “inexperience” may be predisposing factors, although one might equally consider older animals weakened by debilitating diseases to appear equally vulnerable.
…During the initial phases of the serial cat killer persona, there were certain features that raised particular concern for human involvement. One was the location of the mutilation, in that many of the carcasses had been “beheaded” or were missing tails. Our study confirmed that heads, necks, and tails were the most frequently mutilated body parts, but also detected forelimb mutilation at the scapula-body wall articulation, and less often complete carcass transection. These are similar to the scavenging patterns of foxes on lambs, where the nose, ears, tails, and heads are most often missing, but disarticulated limbs and transected spines are also detected. In over half of the cat carcasses predated or scavenged by coyotes, carcass transection was also identified, but individual missing heads, necks, tails, or forelimbs were not. These observations demonstrate clear differences in the mutilation pattern between the coyote and red fox when scavenging cat carcasses, but similarities in the scavenging patterns of the red fox on different but comparably sized species (ie. cats and lambs). Interestingly, when foxes scavenge larger carcasses such as deer they are seen to target extremities or the most decomposed areas in preference to the head or neck, and when cattle are targeted, lips, udders, or genitalia are removed first. A possible explanation for these variations in scavenging patterns between the small and larger carcasses is the increased strength required to dismember larger carcasses. Adult foxes are solitary scavengers and dismantle carcasses on their own, in contrast to dogs and wolves that operate in groups and can tear carcasses apart together with more combined force. Moreover, foxes are also reported to have relatively weak jaws, and thus may remove accessible soft tissues or disarticulate weaker joints that can be more easily gripped. In humans, joints that support more weight such as the knee or lumbar spine decompose more slowly and are more difficult to disarticulate than cervical vertebrae and the scapula, and studies have shown a clear link between the level of autolysis and disarticulation pattern from canine scavenging. This study proposes that the same happens with cat carcasses, as there was frequent disarticulation of cervical vertebrae and scapula, with no evidence of hind limb disarticulation at the hip or stifle joint. Given that most tail disarticulations occurred between Cd2 and Cd5, these joints may either provide good leverage and/or be weaker and decompose more quickly.