Vertebrate scavenging patterns during extreme winter conditions in North Dakota.

The decomposition process for above-the-ground human remains is usually divided into five stages: fresh, bloat, active decay, advanced decay, and skeletal remains. The chronology of these stages is influenced by numerous factors, including environmental temperature, microbial proliferation, necrophagous insect species activity, and vertebrate scavenging. The current research aimed to investigate the vertebrate scavenger's activity during North Dakota winters, using pig carcasses as human analogues. The carcasses were placed outdoors in December 2022, on Mekinock Field Station, Grand Forks County ND, and monitored until the snow melted in May 2023. The monitoring took place daily via trail cameras with motion sensors, while the temperature was recorded hourly using temperature data loggers. The temperature fluctuated between - 32℃ and 30.3℃ along the six experimental months, with a snow cover of up to 130 cm. While the carcasses were covered by snow most of the time, the main vertebrate scavengers observed, represented by coyote (Canis latrans Say, 1823) and the red fox (Vulpes vulpes (Linnaeus, 1758)), dug up corridors to reach and consume the tissues, mostly after sunset. Field based monitoring studies are of tremendous help to understand the factors that induce variation in the chronology of the decomposition stages, invertebrate and vertebrate diversity, and colonization patterns. The current data will be of use to the forensic science field, as it relates to death investigations and search and recovery efforts, by providing an inventory of the primary vertebrate scavengers in this far North location.