Body size and predatory performance in wolves: is bigger better?

Area of Science:

• Ecology
• Zoology
• Behavioral Ecology

Background:

• Large body size in predators can create trade-offs between prey handling and pursuit.
• Understanding these trade-offs is crucial for predator-prey dynamics and evolutionary studies.

Purpose of the Study:

• To investigate the relationship between body size and predatory performance in wolves (Canis lupus).
• To examine how size influences different components of hunting behavior, including strength and locomotor tasks.

Main Methods:

• Longitudinal data from 94 individually identified wolves hunting elk (Cervus elaphus) in Yellowstone National Park.
• Wolf size estimation using a sex-specific growth model based on body mass data from 304 wolves.

Main Results:

• Larger wolves showed improved performance in strength-related tasks (grappling, subduing prey) but not in locomotor tasks (selecting prey) above 39 kg.
• Male wolves outperformed females in attacking, selecting, and killing elk, attributed to sexual dimorphism in size.
• Increasing wolf size conferred an overall predatory advantage despite limitations in locomotor performance.

Conclusions:

• Bigger predators are generally better hunters, but increasing size can limit behaviors requiring high locomotor performance.
• This size limitation may narrow the dietary niche of large carnivores and constrain the evolution of larger body sizes.
• Trade-offs between prey pursuit and handling influence the net predatory benefit of larger predator size.