Extreme hunting efficiency in a carnivorous bat.

Area of Science:

• Ecology
• Animal Behavior
• Predator-Prey Dynamics

Background:

• Large predators typically hunt large prey with high costs and failure rates, while small predators hunt small, abundant prey efficiently.
• Most bats are small predators feeding on insects, but some species exhibit true carnivory, hunting larger vertebrate prey.
• This carnivorous strategy in small bats presents a paradox due to high metabolic demands and the energetic costs associated with hunting large, scarce prey.

Purpose of the Study:

• To investigate the hunting behavior and energetic strategies of carnivorous fringe-lipped bats (Trachops cirrhosus) targeting large vertebrate prey.
• To resolve the paradox of how small bats with high metabolic rates can sustain a hunting strategy involving large, less-abundant prey.

Main Methods:

• Quantified hunting behavior of 20 wild fringe-lipped bats using sound and movement biologging tags.
• Estimated prey size relative to bat body mass and analyzed hunting success rates and time spent in flight.
• Observed prey capture and consumption, including mastication times.

Main Results:

• Fringe-lipped bats hunt prey approximately 7% of their body mass, with potential for prey up to their own size.
• Bats exhibit extreme hunting efficiency, spending only a median of 11% of the night in flight.
• High hunting success rates (median 50%) were achieved through eavesdropping on prey sounds and ambush predation, indicating a low-risk/high-gain strategy.

Conclusions:

• Carnivorous bats employ a specialized, highly efficient hunting strategy that contrasts with typical predator-prey dynamics.
• This low-risk/high-gain strategy is dependent on high prey densities in pristine habitats.
• The specialized nature of this predatory behavior raises concerns for the long-term survival of these bats in the Anthropocene due to habitat changes.