Primate dietary diversity is reflected in their dental morphology, with differences in size and shape of teeth. In particular, the tooth wear angle can provide insight into a species' ability to break down certain foods. To examine dietary and masticatory information, digitized polygon models of dental casts provide a basis for quantitative analysis of wear associated with tooth attrition. In this study, we analyze and compare the wear patterns of Pongo pygmaeus, Gorilla gorilla gorilla and Pan troglodytes schweinfurthii lower molars, focusing on the degree of inclination of specific wear facets. The variation in wear angles appears to be indicative of jaw movements and the specific stresses imposed on food during mastication, reflecting thus the ecology of these species. Orangutans exhibit flatter wear angles, more typical of a diet consisting of hard and brittle foods, while gorillas show a wear pattern with a high degree of inclination, reflecting thus their more leafy diet. Chimpanzees, on the other hand, show intermediate inclinations, a pattern that could be related to their highly variable diet. This method is demonstrated to be a powerful tool for better understanding the relationship between food, mastication and tooth wear processes in living primates, and can be potentially used to reconstruct the diet of fossil species.

Keywords:
Tooth macrowear, Ecology, Diet, Mastication, Living primates
1.
Basabose AK (2002). Diet composition of chimpanzees inhabiting the montane forest of Kahuzi, Democratic Republic of Congo. American Journal of Primatology 58: 1-21.
2.
Benazzi S, Kullmer O, Grosse IR, Weber GW (2011). Using occlusal wear information and finite element analysis to investigate stress distributions in human molars. Journal of Anatomy 219: 259-272.
3.
Benazzi S, Nguyen HN, Kullmer O, Hublin JJ (2013). Unravelling the functional biomechanics of dental feature and tooth wear. PLoS One 8: e69990.
4.
Berthaume M (2014). Tooth cusp sharpness as a dietary correlate in great apes. American Journal of Physical Anthropology 153: 226-235.
5.
Berthaume M (2016). Food mechanical properties and dietary ecology. American Journal of Physical Anthropology 159: S79-S104.
6.
Berthaume MA, Dumont ER, Godfrey LR, Grosse IR (2013). How does tooth cusp radius of curvature affect brittle food item processing? Journal of the Royal Society Interface 10: 20130240.
7.
Bunn JM, Boyer DM, Lipman Y, St Clair EM, Jernvall J, Daubechies I (2011). Comparing Dirichlet normal surface energy of tooth crowns, a new technique of molar shape quantification for dietary inference, with previous methods in isolation and in combination. American Journal of Physical Anthropology 145: 247-261.
8.
Chancellor RL, Rundus AS, Nyandwi S (2012). The influence of seasonal variation on chimpanzee (Pan troglodytes schweinfurthii) fallback food consumption, nest group size, and habitat use in Gishwati, a montane rain forest fragment in Rwanda. International Journal of Primatology 33: 115-133.
9.
Conklin-Brittain NL, Wrangham RW, Hunt KD (1998). Dietary response of chimpanzees and cercopithecines to seasonal variation in fruit abundance. II. Macronutrients. International Journal of Primatology 19: 971-998.
10.
Constantino PJ, Lucas PW, Lee JJ-W, Lawn BR (2009). The influence of fallback foods on great ape tooth enamel. American Journal of Physical Anthropology 140: 653-660.
11.
Dean M, Benyon A (1991). Tooth crown heights, tooth wear, sexual dimorphism and jaw growth in hominoids. Zeitschrift für Morphologie und Anthropologie 3: 425-440.
12.
Delgado AR, van Shaik CP (2000). The behavioral ecology and conservation of the orangutan (Pongo pygmaeus): a tale of two islands. Evolutionary Anthropology 9: 201-218.
13.
Doran DM, McNeilage A (1998). Gorilla ecology and behavior. Evolutionary Anthropology 6: 120-131.
14.
Doran DM, McNeilage A, Greer D, Bocian C, Mehlman P, Shah N (2002). Western lowland gorilla diet, resource availability: new evidence, cross-site comparisons, reflections on indirect sampling methods. American Journal of Primatology 58: 91-116.
15.
Elgart AA (2010). Dental wear, wear rate, and dental disease in the African apes. American Journal of Primatology 72: 481-491.
16.
Emery Thompson M, Wrangham RW (2008). Diet and reproductive function in wild female chimpanzees (Pan troglodytes schweinfurthii) at Kibale National Park, Uganda. American Journal of Physical Anthropology 135: 171-181.
17.
Evans AR, Jernvall J (2009). Patterns and constraints in carnivoran and rodent dental complexity and tooth size. Journal of Vertebrate Paleontology 29: 24A.
18.
Evans AR, Sanson GD (2003). The tooth of perfection: functional and spatial constraints on mammalian tooth shape. Biological Journal of the Linnean Society 78: 173-191.
19.
Evans AR, Sanson GD (2006). Spatial and functional modelling of carnivore and insectivore molariform teeth. Journal of Morphology 267: 649-662.
20.
Evans AR, Wilson GP, Fortelius M, Jernvall J (2007). High-level similarity of dentition in carnivorans and rodents. Nature 445: 78-81.
21.
Every RG (1972). A New Terminology for Mammalian Teeth: Founded on the Phenomenon of Thegosis, parts 1 and 2. Christchurch, Pegasus.
22.
Fiorenza L (2009). Occlusal Wear Pattern Analysis of Functional Morphology in Neanderthals and Early Homo sapiens Dentition. Doctoral dissertation, Goethe University, Frankfurt.
23.
Fiorenza L (2015). Reconstructing diet and behaviour of Neanderthals from Central Italy through dental macrowear analysis. Journal of Anthropological Sciences 93: 1-15.
24.
Fiorenza L, Kullmer O (2013). Dental wear and cultural behaviour in middle paleolithic humans from the near east. American Journal of Physical Anthropology 152: 107-117.
25.
Fiorenza L, Kullmer O (2015). Dental wear patterns in early modern humans from Skhul and Qafzeh: a response to Sarig and Tillier. HOMO - Journal of Comparative Human Biology 66: 414-419.
26.
Fiorenza L, Benazzi S, Bence V, Kullmer O, Friedemanns S (2011a). Relationship between cusp size and occlusal wear pattern in Neanderthal and Homo sapiens first maxillary molar. Anatomical Record 244: 453-461.
27.
Fiorenza L, Benazzi S, Kullmer O (2009). Morphology, wear and 3D digital surface models: material and techniques to create high-resolution replicas of teeth. Journal of Anthropological Sciences 87: 211-218.
28.
Fiorenza L, Benazzi S, Kullmer O (2011b). Para-masticatory wear facets and their functional significance in hunter-gatherer maxillary molars. Journal of Archaeological Sciences 38: 2182-2189.
29.
Fiorenza L, Benazzi S, Moggi-Cecchi J, Menter CG, Kullmer O (2014). Dental macrowear analysis in great apes. American Journal of Physical Anthropology 153(suppl 58): 117-118.
30.
Fiorenza L, Benazzi S, Tausch J, Kullmer O, Bromage TG, Schrenk F (2011c). Molar macrowear reveals Neanderthal eco-geographical dietary variation. PLoS One 6: e14769.
31.
Fiorenza L, Benazzi S, Tausch J, Kullmer O, Schrenk F (2010). Brief communication: identification reassessment of the isolated tooth Krapina D58 through occlusal fingerprint analysis. American Journal of Physical Anthropology 143: 306-312.
32.
Fiorenza L, Benazzi S, Henry AG, Salazar-García DC, Blasco R, Picin A, Wroe S, Kullmer O (2015a). To meat or not to meat? New perspectives on Neanderthal ecology. Yearbook of Physical Anthropology 156, Supplement S59: 43-71.
33.
Fiorenza L, Nguyen HN, Benazzi S (2015b). Stress distribution and molar macrowear in Pongo pygmaeus: a new approach through finite element and occlusal fingerprint analyses. Human Evolution 30: 215-226.
34.
Fleming TH, Breitwisch R, Whitesides GH (1987). Patterns of tropical vertebrate frugivore diversity. Annual Review of Ecology and Systematics 18: 91-109.
35.
Fruth B, Hohmann G, McGrew WC (1999). The Pan species. In The Non-human Primates (Dolhinow P, ed.), pp 64-72. Mayfield, Mountain View.
36.
Goodall J (1986). The Chimpanzees of Gombe. Cambridge, MA, Harvard University Press.
37.
Gordon KD (1982). A study of microwear on chimpanzee molars: implications of dental microwear analysis. American Journal of Physical Anthropology 59: 195-215.
38.
Gordon KD (1984). Orientation of occlusal contacts in the chimpanzee, Pan troglodytes verus, deduced from scanning electron microscopic analysis of dental microwear patterns. Archives of Oral Biology 29: 783-787.
39.
Hammer Ø, Harpen DAT, Ryan PD (2001). PAST: Palaeontological Statistics software package for education and data analysis. Palaentologia Electronica 4: 9.
40.
Harvati K, Darlas A, Bailey SE, Rein TR, El Zaatari S, Fiorenza L, Kullmer O, Psathi E (2013). New Neanderthal remains from Mani peninsula, S. Greece: the Kalamakia Middle Palaeolithic cave site. Journal of Human Evolution 64: 486-499.
41.
Hillson S (2003). Dental Anthropology. Cambridge, Cambridge University Press.
42.
Janis CM (1990). The correlation between diet and dental wear in herbivorous mammals, and its relationship to the determination of diets of extinct species. In Evolutionary Paleobiology of Behavior and Coevolution (Boucot AJ, ed.), pp 241-259. Amsterdam, Elsevier Science.
43.
Kaidonis JA (2008). Tooth wear: the view of the anthropologist. Clinical Oral Investigations 12(suppl 1): 21-26.
44.
Kaidonis JA, Richards LC, Townsend GC (1993). Nature and frequency of dental wear facets in an Australian Aboriginal population. Journal of Oral Rehabilitation 20: 333-340.
45.
Kanamori T, Kuze N, Bernard H, Malim TP, Kohshima S (2010). Feeding ecology of Bornean orangutans (Pongo pygmaues morio) in Danum Valley, Sabah, Malaysia: a 3-year record including two mast fruitings. American Journal of Primatology 72: 820-840.
46.
Kay RF (1973). Mastication, Molar Tooth Structure and Diet in Primates. Doctoral dissertation, Yale University.
47.
Kay RF (1975). The functional adaptation of primate molar teeth. American Journal of Physical Anthropology 43: 195-216.
48.
Kay RF (1978). Molar structure and diet in extant Cercopithecidae. In Development, Function and Evolution of Teeth (Butler PM, Joysey KA, eds.), pp 309-339. New York, Academic Press.
49.
Kay RF, Hiiemae KM (1974). Jaw movement and tooth use in recent and fossil primates. American Journal of Physical Anthropology 40: 227-256.
50.
Kay RF, Hylander WL (1978). The dental structure of mammalian folivores with special reference to primates and Phalangeroidea (Marsupialia). In The Ecology of Arboreal Folivores (Montgomery GG, ed.), pp 173-191. Washington, Smithsonian Institution Press.
51.
Ketch LA, Malloch D, Mahaney WC, Huffman MA (2001). Comparative microbial analysis and clay mineralogy of soils eaten by chimpanzees (Pan troglodytes schweinfurthii) in Tanzania. Soil Biology & Biochemistry 33: 199-203.
52.
Klukkert ZS, Teaford MF, Ungar PS (2012). A dental topographic analysis of chimpanzees. American Journal of Physical Anthropology 148: 276-284.
53.
Krueger KL, Scott JR, Kay RF, Ungar PS (2008). Technical note: dental microwear textures of “phase I” and “phase II” facets. American Journal of Physical Anthropology 137: 485-490.
54.
Kullmer O, Benazzi S, Fiorenza L, Schulz D, Basco S, Winzen O (2009). Technical note: occlusal fingerprint analysis: quantification of tooth wear pattern. American Journal of Physical Anthropology 139: 600-605.
55.
Kullmer O, Benazzi S, Schulz D, Gunz P, Kordos L, Begun DR (2013). Dental arch restoration using tooth macrowear patterns with application to Rudapithecus hungaricus, from the late Miocene of Rudabanya, Hungary. Journal of Human Evolution 64: 151-160.
56.
Kuroda S, Nishihara T, Suzuki S, Oko RA (1996). Sympatric chimpanzees and gorillas in the Ndoki Forest, Congo. In Great Ape Societies (McGrew WC, Marchant LF, Nishida T, eds.), pp 71-81. Cambridge, Cambridge University Press.
57.
Ledogar JA, Winchester JM, St Clair EM, Boyer DM (2013). Diet and dental topography in pitheciine seed predators. American Journal of Physical Anthropology 150: 107-121.
58.
Lucas PW (1979). The dental-dietary adaptations of mammals. Neues Jahrbuch für Geologie und Paläontologie 8: 486-512.
59.
Lucas PW, Luke DA (1984). Chewing it over - basic principles of food breakdown. In Food Acquisition and Processing in Primates (Chivers DJ, Wood BA, Bilsborough A, eds.), pp 283-302. New York, Plenum Press.
60.
Lucas PW, Teaford MF (1994). Functional morphology of colobine teeth. In Colobine Monkeys: Their Ecology, Behaviour and Evolution (Davies AG, Oates JF, eds.), pp 173-203. Cambridge, Cambridge University Press.
61.
Lucas PW, Omar R, Al-Fadhalah K, Almusallam AS, Henry AG, Michael S, Thai LA, Watzke J, Strait DS, Atkins AG (2013). Mechanisms and causes of wear in tooth enamel: implications for hominin diets. Journal of the Royal Society Interface 10: 20120923.
62.
Luke DA, Lucas PW (1983). The significance of cusps. Journal of Oral Rehabilitation 10: 197-206.
63.
MacKinnon JR (1974). The behaviour and ecology of wild orang-utans (Pongo pygmaeus). Animal Behaviour 22: 4-74.
64.
MacKinnon JR (1979). Reproductive behaviour in wild-orang-utan populations. In The Great Apes (Hamburg DA, McCown ER, eds.), pp 194-233. San Francisco, Benjamin-Cummings.
65.
Maier W, Schneck G (1981). Konstruktionsmorphologische Untersuchungen am Gebiss der hominoiden Primaten. Zeitschrift für Morphologie und Anthropologie 72: 127-169.
66.
Maier W, Schneck G (1982). Functional morphology of hominoid dentitions. Journal of Human Evolution 11: 693-696.
67.
Masi S, Cipolletta C, Robbins MM (2009). Western lowland gorillas (Gorilla gorilla gorilla) change their activity patterns in response to frugivory. American Journal of Primatology 71: 91-100.
68.
McGrew WC, Baldwin PJ, Tutin CEG (1988). Diet of wild chimpanzees (Pan troglodytes verus) at Mt. Assirik, Senegal. I. Composition. American Journal of Primatology 16: 213-226.
69.
Merceron G, Blondel C, De Bonis L, Koufos GD, Viriot L (2005). A new method of dental microwear analysis: application to extant primates and Ouranopithecus macedoniensis (Late Miocene of Greece). PALAIOS 20: 551-561.
70.
M'Kirera F, Ungar PS (2003). Occlusal relief changes with molar wear in Pan troglodytes troglodytes and Gorilla gorilla gorilla. American Journal of Primatology 60: 31-41.
71.
Newton-Fisher NE (1999). The diet of chimpanzees in the Budongo Forest Reserve, Uganda. African Journal of Ecology 37: 344-354.
72.
Nishida T, Wrangham RW, Goodall J, Uehara S (1983). Local differences in plant-feeding habits of chimpanzees between Mahale Mountains and Gombe National Park, Tanzania. Journal of Human Evolution 12: 467-480.
73.
Pilbrow V (2007). Patterns of molar variation in great apes and their implications for hominin taxonomy. In Dental Perspectives on Human Evolution (Bailey SE, Hublin JJ, eds.), pp 9-32. Dordrecht, Springer.
74.
Potts KB, Watts DP, Wrangham RW (2011). Comparative feeding ecology of two communities of chimpanzees (Pan troglodytes) in Kibale National Park, Uganda. International Journal of Primatology 32: 669-690.
75.
Poulsen JR, Clark CJ (2004). Densities, distributions, and seasonal movements of gorillas and chimpanzees in swamp forest in northern Congo. International Journal of Primatology 25: 285-306.
76.
Remis MJ (1997). Western lowland gorillas (Gorilla gorilla gorilla) as seasonal frugivores: use of variable resources. American Journal of Primatology 43: 87-109.
77.
Rijksen H (1978). A field study on Sumatran orangutans (Pongo pygmaeus abelii Lesson 1827). Wageningen, Veenman and Zonen.
78.
Rodman P (1977). Feeding behaviour of orangutans of the Kutai Nature Reserve, East Kalimantan. In Primate Ecology (Clutton-Brock T, ed.), pp 383-413. London, Academic Press.
79.
Rogers ME, Maisels F, Williamson EA, Fernandez M, Tutin CEG (1990). Gorilla diet in the Lopé Reserve, Gabon: a nutritional analysis. Oecologia 84: 326-339.
80.
Rogers ME, Maisels F, Williamson EA, Tutin CEG, Fernandez F (1992). Nutritional aspects of gorilla food choice in the Lope Reserve, Gabon. In Topics in primatology Vol. II. Behaviour, ecology, conservation (Itoigawa N, Sugiyama S, Sackett GP, Thompson RKR, eds.), pp 225-240. Tokyo, University of Tokyo Press.
81.
Rogers ME, Abernethy K, Bermejo M, Cipolletta C, Doran D, McFarland K, Nishihara T, Remis M, Tutin CEG (2004). Western gorilla diet: a synthesis from six sites. American Journal of Primatology 64: 173-192.
82.
Scott RS, Teaford MF, Ungar PS (2012). Dental microwear texture and anthropoid diets. American Journal of Physical Anthropology 147: 551-579.
83.
Smith BH (1984). Patterns of molar wear in hunter-gatherers and agriculturalists. American Journal of Physical Anthropology 63: 39-56.
84.
Spears IR, Crompton RH (1996). The mechanical significance of the occlusal geometry of great ape molars in food breakdown. Journal of Human Evolution 31: 517-535.
85.
Stanford CB, Nkurunungi JB (2003). Behavioral ecology of sympatric chimpanzees and gorillas in Bwindi Impenetrable National Park, Uganda: diet. International Journal of Primatology 4: 901-918.
86.
Strait SG (1993). Molar morphology and food texture among small bodied insectivorous mammals. Journal of Mammalogy 74: 391-402.
87.
Sugardjito J, Nurhuda N (1981). Meat-eating behaviour in wild orangutans, Pongo pygmaeus. Primates 22: 414-416.
88.
Swindler DR (2002). Primate Dentition: An Introduction to the Teeth of Non-Human Primates. Cambridge, Cambridge University Press.
89.
Taylor AB (1998). Masticatory form and function in gorillas (G. g. gorilla and G. g. beringei). American Journal of Physical Anthropology 26(suppl): 216-217.
90.
Taylor AB (2002). Masticatory form and function in the African apes. American Journal of Physical Anthropology 117: 133-156.
91.
Taylor AB (2006). Feeding behaviour, diet and the functional consequence of jaw form in orangutans with implications for the evolution of Pongo. Journal of Human Evolution 50: 377-393.
92.
Teaford MF (2007). What do we know and not know about dental microwear and diet? In Evolution of the Human Diet. The Known, the Unknown and the Unknowable (Ungar PS, ed.). Oxford, Oxford University Press.
93.
Teaford MF, Walker AC (1984). Quantitative differences in dental microwear between primate species with different diets and a comment on the presumed diet of Sivapithecus. American Journal of Physical Anthropology 64: 191-200.
94.
Terhune CE (2013). Dietary correlates of temporomandibular joint morphology in the great apes. American Journal of Physical Anthropology 150: 260-272.
95.
Tutin CEG, Fernandez M (1985). Foods consumed by sympatric populations of Gorilla g. gorilla and Pan t. troglodytes in Gabon: some preliminary data. American Journal of Physical Anthropology 6: 27-43.
96.
Tutin CEG, Fernandez M (1993). Composition of the diet of chimpanzees and comparisons with that of sympatric lowland gorillas in the Lopé Reserve, Gabon. American Journal of Primatology 30: 195-211.
97.
Tutin CEG, Fernandez M, Rogers ME, Williamson EA, McGrew WC (1991). Foraging profiles of sympatric lowland gorillas and chimpanzees in the Lopé Reserve, Gabon. Philosophical Transactions of the Royal Society B 334: 179-186.
98.
Uchida A (1998). Variation in tooth morphology in Gorilla gorilla. Journal of Human Evolution 34: 55-70.
99.
Ulhaas L, Kullmer O, Schrenk F (2007). Tooth wear diversity in early hominid molars: a case study. In Dental Perspectives on Human Evolution: State of the Art Research in Dental Paleoanthropology (Bailey S, Hublin JJ, eds.), pp 369-390. Rotterdam, Springer.
100.
Ungar PS, M'Kirera F (2003). A solution to the worn tooth conundrum in primate functional anatomy. Proceedings of the National Academy of Sciences of the United States of America 100: 3874-3877.
101.
Ungar P, Williamson M (2000). Exploring the effect of tooth wear on functional morphology: a preliminary study using dental topographic analysis. Palaeontologia Electronica 3: 1.
102.
Utami SS, Van Hooff JARAM (1997). Meat-eating by adult female Sumatran orangutans (Pongo pygmæus abelii). American Journal of Primatology 43: 159-165.
103.
Walker A, Hoeck HN, Perez L (1978). Microwear of mammalian teeth as an indicator of diet. Science 201: 908-910.
104.
Watts DP (1990). Ecology of gorillas and its relation to female transfer in mountain gorillas. International Journal of Primatology 11: 21-45.
105.
Watts DP (1996). Comparative socio-ecology of gorillas. In Great Ape Societies (McGrew WC, Marchant LF, Nishida T, eds.), pp 16-28. Cambridge, Cambridge University Press.
106.
Watts DP, Potts KB, Lwanga JS, Mitani JC (2012). Diet of chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Kibale National Park, Uganda, 2. Temporal variation and fallback foods. American Journal of Primatology 74: 130-144.
107.
Wich SA, Atmoko SSU, Setia TM, Van Schaik CP (2009). Orangutans: Geographic Variation in Behavioral Ecology and Conservation. Oxford, Oxford University Press.
108.
Williamson ED, Tutin CEG, Rogers ME, Fernandez M (1990). Composition of the diet of lowland gorillas at Lope in Gabon. American Journal of Primatology 21: 265-277.
109.
Wood B, Schroer K (2012). Reconstructing the diet of an extinct hominin taxon: the role of extant primate models. International Journal of Primatology 33: 716-742.
110.
Wrangham RW (1986). Ecology and social relationships in two species of chimpanzee. In Ecological Aspects of Social Evolution (Rubenstein DI, Wrangham RW, eds.), pp 325-378. Princeton, Princeton University Press.
111.
Wrangham RW, Conklin-Brittain NL, Hunt KD (1998). Dietary response of chimpanzees and cercopithecines to seasonal variation in fruit abundance. I. Antifeedants. International Journal of Primatology 19: 949-970.
112.
Yamagiwa J, Basabose AK (2006a). Diet and seasonal changes in sympatric gorillas and chimpanzees at Kahuzi-Biega National Park. Primates 47: 74-90.
113.
Yamagiwa J, Basabose AK (2006b). Effects of fruit scarcity on foraging strategies of sympatric gorillas and chimpanzees. In Feeding Ecology in Apes and Other Primates: Ecological, Physical and Behavioral Aspects (Hohmann G, Robbins MM, Boesch C, eds.), pp 73-96. Cambridge, Cambridge University Press.
114.
Zuccotti LF, Williamson MD, Limp WF, Ungar PS (1998). Modeling primate occlusal topography using geographic information system technology. American Journal of Physical Anthropology 107: 137-142.
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