Carnassial microwear and dietary behaviour in large carnivorans

Abstract

This paper presents the first analysis of dental microwear textures of carnivorans. Carnassial microwear is examined for three large carnivorans, the cheetah Acinonyx jubatus, African lion Panthera leo and spotted hyaena Crocuta crocuta using dental microwear texture analysis, which combines confocal microscopy with the study of scale-sensitive fractal geometry. Results indicate significant differences in the microscopic wear textures of these carnivores consistent with dissimilarities in their reported feeding behaviours. Acinonyx jubatus carnassial shearing facets are characterized by low surface texture complexity and high anisotropy, while P. leo and C. crocuta evince less wear texture anisotropy and more complexity. Panthera leo and C. crocuta have more heavily pitted surfaces, a wider size range of wear features and scratches that vary in their orientations relative to the long axis of the carnassial blade. Further, C. crocuta is most variable in overall surface complexity and also has the highest average complexity values. These results are consistent with differences in bone consumption rates among the three species, wherein cheetahs typically avoid bone, lions triturate it on occasion and spotted hyaenas comminute it more often. Incidences of bone consumption in carnivores reflect degree and/or type of carcass utilization and can be used as a general guide for niche partitioning. Thus, the application of microwear analyses to carnivores can be used to interpret competition and niche position within a guild of fossil carnivores across space and through time.

Dental microwear texture analysis of hominins recovered by the Olduvai Landscape Paleoanthropology Project, 1995–2007

“…Species that consume more hard-brittle foods tend to have higher Asfc and lower epLsar values than closely related taxa that consume softer, tougher items. This holds whether comparing primates, bovids, carnivorans, or macropodid marsupials (Scott et al, 2006;Ungar et al, 2007Ungar et al, , 2010aPrideaux et al, 2009;Schubert et al, 2010). Complexity reflects change in roughness (measured here as the summed area of tiles of a given size laid across a surface divided by the projected or planimetric area of that surface) across scales of observation; it is the steepest slope of the curve fitted to a plot of relative area versus scale over an order of magnitude.…”

Osteophagy by the Grizzly Bear,Ursus arctos

“…However, grizzly bears predate and scavenge ungulates when available, significantly increasing digestible protein and other nutrients in their diets at this time (MacHutchon and Wellwood 2003). Additionally, like other carnivores, bears consume bone fragments while feeding on recently killed or scavenged carcasses (Phillips 1993, Schubert et al 2010. Although it is reasonable to expect bears to chew on antlers at the carcass site (personal observation), there are no published reports or observations of bears actively seeking out and consuming shed antlers.…”

A Dental Microwear Texture Analysis of the Mio-Pliocene Hyaenids from Langebaanweg, South Africa

“…Dental microwear analysis.-Dental microwear analysis has been widely used to examine aspects of diet and ecology in primates (Rafferty and Teaford 1992;Lucas and Teaford 1994;Teaford et al 1996;Ungar 1996Ungar , 1998Ungar and Teaford 1996;Ungar et al 2004), artiodactyls (Solounias et al 1988;Solounias and Moelleken 1993;Rivals and Deniaux 2003;Merceron et al 2004Merceron et al , 2005bFranz−Odendaal and Solounias, 2004;Semprebon et al 2004;Merceron and Ungar 2005;Schubert et al 2006;Ungar et al 2007) and, to a lesser extent, other taxa, including carnivorans (see Taylor and Han− nam 1987;Van Valkenburgh et al 1990;Anyonge 1996;Goillot et al 2009;Schubert et al 2010;Ungar et al 2010). Conventional techniques used to assess dental microwear im− age surfaces employ either a scanning electron microscope (Rensberger 1978;Teaford and Walker 1984;Grine et al 2002) or a light stereomicroscope combined with image anal− ysis software (Merceron et al 2005a(Merceron et al , 2010bCalandra et al 2008;Peigné et al 2009) to count and measure individual fea− tures (pits and scratches) on occlusal surfaces.…”

“…Be− cause microwear signatures reflect the mechanical properties of foods actually eaten by individuals, dietary inferences are not greatly affected by adaptationist assumptions. Here we employ dental microwear texture analysis (RS Scott et al 2005Ungar et al 2008Ungar et al , 2010JR Scott et al 2009;Merceron et al 2010a;Schubert et al 2010) to inform on durophagy levels in Hyaenictitherium namaquensis, Ikelo− hyaena abronia, Chasmaporthetes australis, and Hyaenictis hendeyi from the South African Mio−Pliocene fossil site of Langebaanweg (LBW) E Quarry (32°582S, 18°72E) (Hendey 1981(Hendey , 1982(Hendey , 1984Roberts 2006). These four taxa fall into three adaptive types or ecomorphologies (ecomorphs) (Wer− delin and Solounias 1996;Turner et al 2008) that dominated the hyaena evolutionary record immediately prior to the pro− liferation of developed bone−cracking taxa.…”

“…2010;Schulz et al 2010), and marsupials (Prideaux et al 2009). In its first application to carnivorans, Schubert et al (2010) compared carnassial microwear in three large feliforms, Acinonyx juba− tus (the cheetah), Panthera leo (the lion), and Crocuta crocuta (the spotted hyaena). These authors demonstrated that in− creased durophagy in feliform carnivorans results in an in− crease in microwear surface pittedness or complexity (higher Asfc), an increase in microwear surface feature size (higher Tfv) and a decrease in feature orientation (lower epLsar).…”