The remains were part of a taphonomic experiment at the Forensic Anthropology Research Facility (FARF) in Texas, USA, where they were studying what types of scavengers visit human carcasses. They were left uncovered with cameras photographing anything that came to scavenge them. Imagine being the person reviewing those images, expecting to see coyotes, or racoons, or turkey vultures, and instead uncovering the first recorded instance of human bone-munching deer.
Image from Meckel et al. (2017).
Herbivorous animals practice osteophagy when they need more phosphate, calcium, and other nutrients in their diet. Porcupines, giraffes, cows, and even tortoises have been seen chewing on bones, most often already dry and easily accessible bones like ribs.
When recording traces of tooth-marks on bones in the modern, archaeological, or palaeontological record, it is important to remember that not all scavengers that interact with carcasses are trying to consume flesh. And that while carnivorous scavengers typically eat soft tissue and fresh bone leaving behind puncture holes and pits, bone-eating herbivores chew on the ends of older bones with teeth normally used to eat plants leaving behind long scores and forked splinters.
Meckel, L. A., McDaneld, C. P., Wescott, D. J., 2017. White-tailed Deer as a Taphonomic Agent: Photographic Evidence of White-tailed Deer Gnawing on Human Bone. DOI: 10.1111/1556-4029.13514.