There are multiple ways, most rely on contextual clues.

Analysis of cut- marks can indicate whether people were butchered or defleshed. Comparison of the treatment of human remains with animal remains from the same site can increase confidence that the butchery was geared towards the consumption of people.

Similarly, the degree of burning of human bones can be recorded and compared to how animal remains from the same context were treated.

Damage/polish patterns indicative of boiling in pots are sometimes present on human bones, indicating cooking of some sort.

I guess the only way to really definitively prove cannibalism is from the analysis of human tissue in human coprolites.

One of the landmark works on the identification of cannibalism from bone assemblages is: 

White, T.D., 1992: Prehistoric Cannibalism at Mancos 5MTUMR-2346, Princeton University Press.

Papers on possible cannibalism in the Pleistocene at Klasies River are also of interest here... Yes and the coprolite papers are great to look at - http://www.sciencemag.org/news/2000/09/anasazi-ate-their-enemies.

Hi

Maybe there You can find some informations

M. Żurawiecka 2015; Kanibalizm w pradziejach, "Antropogen", 1: 15-18.

http://83.144.117.98/KNAUJ/Antropogen/wydania/Antropogen-01-2015.pdf

Best Regards

Maciej Wawrzczak

Hi April:

Can be investigated by myoglobin test in coprolites, and dental analysis bioliths.

Regards.

An issue is that cut-marks and pot polish on human skeletal material could be the result of funerary activities that are not part of mortuary cannibalism (the eating of one's own dead). However, crushed bones to release marrow, especially those that show signs of pot polish and butchering marks, are likely the result of cannibalism. 

Hi April

I guess you can find some answers in Paola Villa's paper on cannibalism in the Fonbregoua cave in south of France. The paper is in French but she wrote a note for Science n°233 in English. Michael Pickering doesn't agree with her opinion and here is his paper. You may also find a lot from Bruno Boulestin's papers which are available on academia.edu.Here are some of the papers I mentionned and others found on academia;edu or researchgate

Yours

Anne

www.academia.edu/7822314/The_ethnographic_historical_and_archaeological_evidence_for_the_practice_of_institutionalised_anthropophagy

Aside from other signs already mentioned, let's not forget the dental markings themselves. Humans tend to cut the meat with the incisors first, then grind the meat from the bones with molars & premolars. That's a completely different pattern than what other meat-eating mammals do (e.g., large felines). The latter tear the meat from the bones with very sharp canines and molars and their molar cusps (pointy) leave distinct marks on bones than what human teeth would do. Human cusps are small and almost flat (low and rounded in shape) compared to other carnivorous mammals (including all other meat-eating primates like chimpanzee and many monkeys whose molar cusps are high and pointy. To me the teeth markings are the most relevant sign.

Many recent studies in the US Southwest:

Man Corn by Christy Turner is the major review, he lays out criteria for recognizing it in osteological samples. I think his final interpretation of Mesoamerican influence is not well supported.

Bryant, Vaughn M., and Karl J. Reinhard                                      x

2012  Coprolites and Archaeology: The Missing Links in Understanding Human Health. In Vertebrate Coprolites, edited by Hunt et al., New Mexico Museum of Natural History and Science Bulletin 57:379-387.

History of copro studies reviewed, emph on SW. In SW, understand prevalence of diabetes and obesity in mod Ind pops. Copros show link between parasite load in SW and cribra orbitalia/ porotic hyperostosis - pinworm and others affect B12, but also show that even hard times, puebloans had access to small game meat. Copro evidence of cannibalism, but also shows was not normal. 

Reinhard, Karl

2006 A Coprological View of Ancestral Pueblo Cannibalism. American Scientist 94:254-261.

Cannibalism claims might “taint the image of this modern culture by the characterization of their ancestors” and “undo 20 years of my research on Ancestral Pueblo diet.” Experience with Anasazi copros shows diet was high in wild plants and small animals even when agric important. Meat always eaten with plant food. Distinctive regional cuisines possible: e.g. maize-beeweed-purslane + corn smut in BM from Turkey Pen Cave. Also evidence of starvation foods, showing versatile adaptation and refuting idea of starvation cannibalism. But he analyzed Cowboy Wash copro, showed a pure meat diet, unlike normal Anasazi. Then R. Marlar used enzyme-linked immunosorben assay to detect human myoglobin: “The coprolite was from a human who had eaten another human.” But because this is not normal Anasazi diet, must be a non-Ancestral Pueblo. [This lets him have it both ways: cannibalism did occur, but not by our friends the modern Pueblos. But of course it begs the question of who the cannibal was, and ignores the skeletal evidence from many sites.]

While I do not keep up with it, the last I heard was that there is not many substantiated cases of cannibalism in the world. Most confirmed cases have been extreme starvation or cases of ritualistic consumption. Although my first thought was teeth marks, there have been a few research papers that have cast doubt on previous identifications of human teeth marks on human bone.

The attached chapter addresses this question.

The attached  paper , sorry in French , could give, from marine context and cut-marks, an idea of a Richard Parker's type cannibalism of necessity.

Christopher,

Thank you for posting Chapter 17. I think the statement of "These are considered unusual because they occur as multiple burials in the same stratum, lack grave good inclusions, and possess no standard body position or spatial location, a pattern that is different from the contemporary burial norm in the region – what the Turners refer to as ‘considerate burial’" is erroneous. First, burial practices change. However, at the Discovery Site near Larose, Louisiana, we had 37 individuals that were represented by cremations, primary prone position, primary supine position, secondary burial, and random unknown placement. Secondary burials included bundle burials and isolated skulls. This is significant because the site was an early Plaquemine cultural (AD 1200-1500) occupation in sealed context. There was sterile alluvial deposits capping the occupation and sterile deposits immediately below the occupation. As such, this site illustrated the complexity of burial practices in just this one assumed egalitarian society. In fact, one burial feature consisted of 6 craniums deposited in a bundle with long bones exclusively. There also is the fact that some burials had grave goods, while others did not.

In addition, the Caddoan people (AD 900-1700) in the NW Louisiana, NE Texas, SE Oklahoma, SW Arkansas region often buried their dead in pits against the inside or outside wall of the hut, with or without grave goods. These burials could be flexed or extended. They also buried their dead in cemeteries that contained cremations, supine, flexed, isolated, bundled, upright, etc. Thus what exactly is "the contemporary burial norm in the region"?

According to historical accounts, the Attakapas Indians that inhabited the marshes and prairies of southwest Louisiana were cannibals. There is supposedly at least one eye-witness account of a party of three Europeans being captured, with one witnessing a fellow captive being eaten. Atakapa means "eater of men" in the Choctaw language. Kniffen, Gregory, and Stokes (1987:44) says that the Attakapas performed ritualistic cannibalism by eating a part of their slain enemy, whether this was for power/strength or to honor is not said.

How much of this was for "outsider education" is unknown. One early explorer, visiting the aforementioned Caddo on the Red River in NW Louisiana, asked them what was to the south of their territory. Their reply was (paraphrased) "You don't want to go there. They eat people." What better way to keep unwanted people out of your territory!

Regards,

JAG

Nowadays, ther are exciting new ways of carrying out quantitative

work in archeology via shape analysis. For instance, C.G. Small

in his book "The Staistical Theory of Shape" discusses a variety

of applications to the field of archeology. In particular, in Chapter 1

he discusses quantitative measures for the shapes of skulls which

could be useful in this type of research.

Regards,

Theo Odijk, Lorentz Institue for Theoretical Physics

Hi April,

Please keep in mind that my answer regarding teeth markings responds to your specific question about "a way to identify cannibalism through osteology?If your question would have been 'how to identify cannibalism' then there are other routes, such as coprolites, etc., which do not apply to your question I think. So I still stand by my answer that the most specific, tell-tale signs are the human dentition markings on bone, although these markings may not always be present when meat was cut from bone with sharp objects prior to consumption, in which case you would need other methods to find out, e.g. dietary signs (which will be difficult to prove as well). But again, if you are talking about osteological signs, the teeth markings are unique and unmistakable.

See as an example the buried skeletons from the site Herxheim in West Germany (http://www.projekt-herxheim.de/menschen.htm). Here the link to published literature: http://www.projekt-herxheim.de/literatur.htm

Gough's Cave, UK Upper Palaeolithic example:

https://www.researchgate.net/publication/275102518_Upper_Palaeolithic_ritualistic_cannibalism_at_Gough's_Cave_SomersetUK_THE_human_remains_from_head_to_toe

http://www.nhm.ac.uk/press-office/press-releases/palaeolithic-remains-prove-cannibalistic-habits-of-human-ancesto.html

Cheers, Fred.

Article Upper Palaeolithic ritualistic cannibalism at Gough's Cave (...

General overview of the Gough's Cave finds:

http://www.bbc.co.uk/earth/story/20161011-the-people-who-ate-each-other

Who would like to comment on Herxheim ?

identification of human tooth marks

Flinn, L., Turner, C. G., II, Brew, A. Additional Evidence for Cannibalism in the Southwest: The Case of LA 4528. Am Antiquity 1976, 41:308-318.

Graver, S., Sobolik, K. D., Whittaker, J. Cannibalism or Violent Death Alone? Human Remains at a Small Anasazi Site. In Advances in Forensic Taphonomy: Method, Theory, and Archaeological Perspectives; Haglund, W. D., Sorg, M. H., Eds.; CRC Press: Boca Raton (FL), 2002; 309-320.

Lambert, P. M., Billman, B. R., Leonard, B. L. Explaining Variability in Mutilated Human Bone Assemblages from the American Southwest: A Case Study from the Southern Piedmont of Sleeping Ute Mountain, Colorado. Int J Osteoarchaeol 2000, 10:49-64.

Ogilvie, M. D., Hilton, C. E. Ritualized Violence in the Prehistoric American Southwest. Int J Osteoarchaeol 2000, 10:27-48.

Turner, C. G., II. Cannibalism in Chaco Canyon: The Charnel Pit Excavated in 1926 at Small House Ruin by Frank H. H. Roberts, Jr. Am J Phys Anthropol 1993, 91:421-439.

Turner, C. G., II, Turner, J. A. The First Claim for Cannibalism in the Southwest: Walter Hough’s 1901 Discovery at Canyon Butte Ruin 3, Northeastern Arizona. Am Antiquity 1992, 57:661-682.

Turner, C. G., II, Turner, J. A. Man Corn: Cannibalism and Violence in the Prehistoric American Southwest. University of Utah Press: Salt Lake City (UT), 1999.

White, T. D. Prehistoric Cannibalism at Mancos 5MTUMR-2346. Princeton University Press: Princeton (NJ), 1992.

Hurlbut, S. A. The Taphonomy of Cannibalism: A Review of Anthropogenic Bone Modification in the American Southwest. Int J Osteoarchaeol 2000, 10:4-26.

Hardesty, D. L. The Archaeology of the Donner Party. University of Nevada Press: Reno (NV), 1997.

Marlar, R. A., Leonard, B. L., Billman, B. R., Lambert, P. M., Marlar, J. E. Biochemical Evidence of Cannibalism at a Prehistoric Puebloan Site in Southwestern Colorado. Nature 2000, 407:74-78.

Reinhard, K. J. A Coprological View of Ancestral Pueblo Cannibalism: Debate Over a Single Fecal Fossil Offers a Cautionary Tale of the Interplay between Science and Culture. Am Sci 2006, 94:254-261.

Landt, M. J. Tooth Marks and Human Consumption: Ethnoarchaeological Mastication Research among Foragers of the Central African Republic. J Archaeol Sci 2007, 34:1629-1640.

Fernández-Jalvo, Y., Andrews, P. When Humans Chew Bones. J Hum Evol 2011, 60:117-123.

Turner, C. G. Taphonomic Reconstructions of Human Violence and Cannibalism Based on Mass Burials in the American Southwest. In Carnivores, Human Scavengers, and Predators: A Question of Bone Technology, LeMoine, G. M., MacEachern, A. S., Eds.; Archaeological Association of the University of Calgary: Calgary, Canada, 1983; 219-240.

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You can find extensive information about Herxheim in Boulestin, B., Coupey, A.-S., 2015. Cannibalism in the Linear Pottery Culture: The Human Remains from Herxheim. Archaeopress Publishing Limited.

On the other hand, Antonio Rodríguez-Hidalgo and me published a summary about prehistoric cannibalism in Europe, where you can find what are the most common signals on the bones of these assemblages:

Saladié, P., Rodríguez-Hidalgo, A., 2017. Archaeological Evidence for Cannibalism in Prehistoric Western Europe: from Homo antecessor to the Bronze Age. Journal of Archaeological Method and Theory. 24, 1034–1071.

Best!

A general look on the Chasséen burial practices seems to be necesary.

Look at:

Turner, C.G. & J.A. Turner. 2011. Man Corn: Cannibalism and Violence in the Prehistoric American Southwest. University of Utah Press.

White, T.D. 1992. Prehistoric Cannibalism at Mancos 5MTUMR-2346. Princeton University Press.

Warm weather pushed Neanderthals into cannibalism

https://cosmosmagazine.com/archaeology/warm-weather-pushed-neanderthals-into-cannibalism

https://www.dailymail.co.uk/sciencetech/article-6876527/Neanderthals-resorted-CANNIBALISM-thanks-climate-change-120-000-years-ago.html

https://www.history.com/news/neanderthal-cannibalism-baume-moula-guercy-discovery

Neanderthal cannibalism is less surprising than you think

https://arstechnica.com/science/2019/03/climate-change-may-have-driven-a-band-of-neanderthals-to-cannibalism/

McLaughlin, S. 2005. Cannibalism and Easter Island: evaluation, discussion of probabilities, and survey of the literature on the subject. Rapa Nui Journal 19 (1): 30-50.

For a more isotopic analysis, the C/N plot would show a higher trophic level than anything else in the food web of that specific geographical location. For example, anything higher than 24 for Nitrogen would be evident or at least inferable. One caveat is that you would need the archaeological context to further support this and isotopes alone are not robust enough to give you an exact answer for this.

DEGUSTA, D. 1999. Fijian Cannibalism: Osteological Evidence from Navatu. American Journal of Physical Anthropology, 110, 215-241.

DEGUSTA, D. 2000. Fijian Cannibalism and Mortuary Ritual: Bioarchaeological Evidence from Vuda. International Journal of Osteoarchaeology, 10, 76-92.

One way to confirm the evidence of cannibalism, is Analysis of cut-marks on the bone