has suggested that times were tougher, or perhaps harder, at La
Brea than for modern analogous carnivore guilds, as carnivores
are inferred to have more fully utilized carcasses, based on
incidences of tooth breakage [10–12]. Specifically, P. atrox has the
greatest incidence of tooth breakage of canines (36%) while S.
fatalis has the lowest incidence for extinct Pleistocene taxa (11.2%)
[11]. These data contrast with those for extant large carnivorans,
which have average canine breakage of ,7%, including felid
values averaging between 3.2% to 9.8% (in the jaguar, Panthera
onca and leopard, Panthera pardus, respectively) and hyaenid values
averaging between 8.3 to 9.6% (in the striped hyena, Hyaena hyaena
and spotted hyena, Crocuta crocuta, respectively) [11]. While tooth
breakage is used as a proxy for carcass utilization, it is also possible
that increased tooth breakage in extinct taxa is a result of
carnivorans taking down larger prey. While Van Valkenburgh and
Hertel [10] exclude this explanation because both prey and
predator sizes are larger during the Pleistocene, it is important to
note that larger predators have relatively weaker teeth for a given
tooth shape (e.g., canines can support a smaller percentage of an
animal’s body weight with increased body size) [13–15].
The analysis of the microscopic wear features left during the
processing of food can also be used to infer extant and extinct diets
including relative durophagy (e.g., [16–18]). High-resolution
SEM-based microwear feature analysis demonstrates a lower