Influence of Diet on the Jaws and Face of the American Eskimo

Waugh, Leuman M.

doi:10.14219/jada.archive.1937.0295

Cited by 32 publications

(18 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our estimates for theoretical maximum bite forces in H. sapiens exceed mean values obtained for voluntary bite force taken from modern western populations (365 N; Sinn et al 1996;to 965 N;Pruim et al 1980), but are close to the mean for the only published data available for a hunter -gatherer population, a large sample of Inuit (1235 N; Waugh 1937). No direct data were available for other taxa.…”

Section: Resultssupporting

confidence: 69%

The craniomandibular mechanics of being human

et al. 2010

View full text Add to dashboard Cite

Diminished bite force has been considered a defining feature of modern Homo sapiens, an interpretation inferred from the application of two-dimensional lever mechanics and the relative gracility of the human masticatory musculature and skull. This conclusion has various implications with regard to the evolution of human feeding behaviour. However, human dental anatomy suggests a capacity to withstand high loads and two-dimensional lever models greatly simplify muscle architecture, yielding less accurate results than threedimensional modelling using multiple lines of action. Here, to our knowledge, in the most comprehensive three-dimensional finite element analysis performed to date for any taxon, we ask whether the traditional view that the bite of H. sapiens is weak and the skull too gracile to sustain high bite forces is supported. We further introduce a new method for reconstructing incomplete fossil material. Our findings show that the human masticatory apparatus is highly efficient, capable of producing a relatively powerful bite using low muscle forces. Thus, relative to other members of the superfamily Hominoidea, humans can achieve relatively high bite forces, while overall stresses are reduced. Our findings resolve apparently discordant lines of evidence, i.e. the presence of teeth well adapted to sustain high loads within a lightweight cranium and mandible.

show abstract

Section: Resultssupporting

confidence: 69%

The craniomandibular mechanics of being human

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Therefore, it is reasonable to expect our modeled bite force values to exceed actual recorded force values. Furthermore, with the exception of those reported by Waugh (1937), the bite-force values were produced by subjects who were unlikely to have engaged in excessive masticatory and/or paramasticatory behavior. In contrast, our recent human sample consisted primarily of individuals who undoubtedly engaged in both such behaviors.…”

Section: Model Validationmentioning

confidence: 80%

“…Given their well-developed masticatory systems, it is reasonable to expect the bite-force estimates of our sample to be higher than reported experimental values. This expectation is reinforced by the bite forces measured in Alaskan Eskimos (Waugh, 1937), a population for whom frequent, heavy use of the masticatory system is welldocumented (Hylander, 1977). This intense use of their teeth and jaws is reflected in the rather large value for molar bite force shown in Table 2.…”

Section: Model Validationmentioning

confidence: 98%

Bite force production capability and efficiency in Neandertals and modern humans

O'Connor

Franciscus

Holton

2005

Am. J. Phys. Anthropol.

103

View full text Add to dashboard Cite

Although there is consensus that Neandertal craniofacial morphology is unique in the genus Homo, debate continues regarding the precise anatomical basis for this uniqueness and the evolutionary mechanism that produced it. In recent years, biomechanical explanations have received the most attention. Some proponents of the "anterior dental loading hypothesis" (ADLH) maintain that Neandertal facial anatomy was an adaptive response to high-magnitude forces resulting from both masticatory and paramasticatory activity. However, while many have argued that Neandertal facial structure was well-adapted to dissipate heavy occlusal loads, few have considered, much less demonstrated, the ability of the Neandertal masticatory system to generate these presumably heavy loads. In fact, the Neandertal masticatory configuration has often been simultaneously interpreted as being disadvantageous for producing large bite forces. With rare exception, analyses that attempted to resolve this conflict were qualitative rather than quantitative. Using a three-dimensional digitizer, we recorded a sequence of points on the cranium and associated mandible of the Amud 1, La Chapelle-aux-Saints, and La Ferrassie 1 Neandertals, and a sample of early and recent modern humans (n = 29), including a subsample with heavy dental wear and documented paramasticatory behavior. From these points, we calculated measures of force-production capability (i.e., magnitudes of muscle force, bite force, and condylar reaction force), measures of force production efficiency (i.e., ratios of force magnitudes and muscle mechanical advantages), and a measure of overall size (i.e., the geometric mean of all linear craniofacial measurements taken). In contrast to the expectations set forth by the ADLH, the primary dichotomy in force-production capability was not between Neandertal and modern specimens, but rather between large (robust) and small (gracile) specimens overall. Our results further suggest that the masticatory system in the genus Homo scales such that a certain level of force-production efficiency is maintained across a considerable range of size and robusticity. Natural selection was probably not acting on Neandertal facial architecture in terms of peak bite force dissipation, but rather on large tooth size to better resist wear and abrasion from submaximal (but more frequent) biting and grinding forces. We conclude that masticatory biomechanical adaptation does not underlie variation in the facial skeleton of later Pleistocene Homo in general, and that continued exploration of alternative explanations for Neandertal facial architecture (e.g., climatic, respiratory, developmental, and/or stochastic mechanisms) seems warranted.

show abstract

“…That is, humans likely do not produce the forces necessary to create mandibular stresses equivalent to those in Great Apes given the amount of bone we utilize. Comparative data on muscle force are hard to come by, but healthy human subjects may typically produce bite forces in the range of 350-1235 N [28][29][30][31][32], and theoretical analysis suggests that forces between 700 and 1300 N are possible [33,34]. By contrast, gorillas and chimpanzee bite force capability may exceed 1500 N [34], and orangutans are probably capable of approaching 2000 N of occlusal force [35].…”

Section: Shifting Masticatory Demandsmentioning

confidence: 99%

The Human Mandible and the Origins of Speech

Daegling

2012

Journal of Anthropology

View full text Add to dashboard Cite

Among the unique traits of human mandibles is the finding of relatively greater utilization of cortical bone with respect to other hominoids. The functional significance of this trait is not plausibly linked to masticatory demands given the diminution of the masticatory musculature in human evolution and the behavioral universal of extraoral food preparation in recent humans. Similarly, the presence of more mandibular bone is not a correlated effect of systemic skeletal robusticity, since gracilization of the skeleton is a feature diagnostic of modern humans. The mandibular symphysis in modern humans is manifested as the chin, and it is here where cortical bone hypertrophy is most pronounced. The potential covariation between the expression of the chin and bone hypertrophy is explored in an attempt to clarify their respective biomechanical roles. Current developments in skeletal biomechanics implicate low magnitude, high frequency strains in bone hypertrophy. The physiology of speech production likely produces strains in mandibular bone of greater frequency and lesser magnitude than those associated with mastication. Consequently, language acquisition plausibly accounts for cortical hypertrophy in modern human mandibles. Its role in the evolution and development of the chin is less clear.

show abstract

Influence of Diet on the Jaws and Face of the American Eskimo

Cited by 32 publications

References 0 publications

The craniomandibular mechanics of being human

The craniomandibular mechanics of being human

Bite force production capability and efficiency in Neandertals and modern humans

The Human Mandible and the Origins of Speech

Contact Info

Product

Resources

About