The Costs of Carnivory

Abstract

Mammalian carnivores fall into two broad dietary groups: smaller carnivores (<20 kg) that feed on very small prey (invertebrates and small vertebrates) and larger carnivores (>20 kg) that specialize in feeding on large vertebrates. We develop a model that predicts the mass-related energy budgets and limits of carnivore size within these groups. We show that the transition from small to large prey can be predicted by the maximization of net energy gain; larger carnivores achieve a higher net gain rate by concentrating on large prey. However, because it requires more energy to pursue and subdue large prey, this leads to a 2-fold step increase in energy expenditure, as well as increased intake. Across all species, energy expenditure and intake both follow a three-fourths scaling with body mass. However, when each dietary group is considered individually they both display a shallower scaling. This suggests that carnivores at the upper limits of each group are constrained by intake and adopt energy conserving strategies to counter this. Given predictions of expenditure and estimates of intake, we predict a maximum carnivore mass of approximately a ton, consistent with the largest extinct species. Our approach provides a framework for understanding carnivore energetics, size, and extinction dynamics.

The Structure of the Mammalian Predator Guild in the Santa Cruz Formation (Late Early Miocene)

“…tricuspidatus , there is a clear positive correlation between body mass and hypercarnivory, as observed in placental predators (Van Valkenburgh et al 2004;Raia et al 2012). This is consistent with the energy balance in acquiring large body masses that require the consumption of larger prey and larger quantities of meat (Carbone et al 1999(Carbone et al , 2007Van Valkenburgh et al 2004).…”

Phylogenetic and functional diversity in large carnivore assemblages

“…I included species whose body mass averages 10 kg or more, hence both including large carnivores (as defined from energetic models [25]) and mesocarnivores [21] in the assessment.…”

How Did Past Environmental Change Affect Carnivore Diversity and Home-Range-Size in Spain?

“…Van Valkenburgh (1985,1988,1989) confined large terrestrial carnivore guilds to predators weighting 7 kg or more (jackal size and larger), proposing this size threshold because of the evidence in extant species for strong competitive interactions among carnivores larger than 7 kg, being weaker among smaller carnivores; in addition, the representation of large carnivores in the fossil record is better. On the other hand, because larger predators achieve a higher net gain rate by concentrating on large prey, Carbone et al (2007) predicted the threshold of 14.5 kg, where predators switch from small to large prey. We follow this criterion, and restrict our study to species of the three families that include top terrestrial predators: Canidae, Felidae and Hyaenidae.…”

“…Figure 4 documents the patterns of HR-size change through time. Reference lines represent the predicted threshold of 14.5 kg where predators switch from small to large prey (Carbone et al, 2007). In general, the HR-size for Canidae decreases during the Pliocene, independently of which estimation of HR-size is considered (family, habitat preference and trophic categories).…”