The costs of carnivory

Area of Science:

• Zoology
• Ecology
• Physiology

Background:

• Mammalian carnivores exhibit distinct dietary strategies based on body mass, with smaller species consuming small prey and larger species specializing in large vertebrates.
• Understanding the energetic constraints and scaling relationships is crucial for predicting carnivore size limits and extinction dynamics.

Purpose of the Study:

• To develop a predictive model for mass-related energy budgets and size limitations in mammalian carnivores.
• To investigate the energetic trade-offs associated with prey size selection and their impact on carnivore energetics.

Main Methods:

• Development of a model to predict energy budgets and size limits based on body mass and dietary groups.
• Analysis of energy expenditure and intake scaling with body mass across different carnivore size classes.
• Estimation of maximum carnivore mass based on predicted energetic constraints.

Main Results:

• The transition to large prey maximizes net energy gain for larger carnivores, despite a 2-fold increase in energy expenditure and intake.
• Energy expenditure and intake exhibit a three-fourths scaling with body mass across all species, with shallower scaling within individual dietary groups.
• A maximum carnivore mass of approximately one ton is predicted, aligning with fossil records of extinct megafauna.

Conclusions:

• Carnivore size is constrained by energetic budgets, with intake limitations influencing energy conservation strategies at the upper size limits.
• The model provides a framework for understanding carnivore energetics, size evolution, and extinction risks.
• Dietary specialization and energetic efficiency play key roles in determining the maximum attainable body size in mammalian carnivores.