Eavesdropping to learn to hunt

A team of researchers from the University of Maryland, US, have found that Big brown bats learn to hunt by eavesdropping on the sonar of other bats,

Many bat species are gregarious. Their capacity for learning from conspecifics has not been fully investigated. Here the researchers tested whether big brown bats (Eptesicus fuscus) can learn a novel foraging task by interacting with knowledgeable conspecifics.

Young bats that flew with "experienced" bats that had been trained to find the worm were very quick to find the treat alone.

In experimental trials, 11 naïve bats (7 juveniles, 4 adults) interacted with trained bats that were trained to capture tethered mealworms. In control trials, 11 naïve bats (7 juveniles, 4 adults) flew with untrained bats. Naïve bats were then assessed for their ability to capture tethered mealworms.  No bat in the control group learned the task. Against this a significant number of experimental bats, including juveniles with little or no experience foraging, showed evidence of learning. Eighty-two per cent of experimental bats and 27% of control bats directed feeding buzzes at the mealworm. Seven experimental bats (64%) showed evidence of learning by attacking and/or capturing the mealworm, while no bat in the control group attacked or captured the prey.

The team filmed the bats as they flew and then examined the bats' movements from successive frames of the footage. They found that whenever an experienced bat found the worm and let out a "feeding buzz” the naive bat flew very close to the demonstrator.

The researchers say their results amply demonstrate that social interaction with experienced bats, and listening to feeding buzzes in particular, may play an integral role in development of foraging skills in bats.

Journal Reference

Social learning of a novel foraging task by big brown bats, Eptesicus fuscus

Genevieve Spanjer Wright, Gerald S. Wilkinson, and Cynthia F. Moss

Animal Behaviour