Urban brown rats have demonstrated an unprecedented predatory behavior: snatching bats out of the air, raising new concerns for bat conservation in populated areas. Researchers documented the attacks at a bat hibernation site near Hamburg, Germany, revealing a highly effective hunting strategy.
Unexpected Predation Observed
Biologists studying a colony of 30,000 bats discovered the rat attacks while monitoring the cave entrance with infrared cameras. The setup was intended to track bat activity, but instead revealed brown rats (Rattus norvegicus ) climbing into the protected kiosk and ambushing bats in flight.
The rodents use their hind legs and tails for balance while grabbing bats mid-air or as they land. They kill the prey with a single bite and drag away the carcasses. Out of 30 attempted attacks, the rats were successful in 13 cases.
Hunting in Darkness
The attacks occur in complete darkness, leading researchers to believe the rats rely on their whiskers to sense the bats’ presence. “You can really see that the rats seem to be experts,” says Yossi Yovel, a neuro-ecologist, highlighting the precision and efficiency of the behavior.
The discovery is significant because it demonstrates a new, highly effective predation method. A colony of just 15 rats could reduce a 30,000-bat population by 7 percent each winter, according to estimates.
Conservation Implications
The rise of rat predation poses a substantial threat to urban bat populations. Invasive brown rats are widespread in European cities, forcing bats to adapt to a new and formidable predator.
Researchers emphasize the need for rat mitigation strategies at bat hibernation sites to protect vulnerable colonies. The ability of rats to hunt bats in mid-flight underscores the urgency of addressing this emerging threat to bat conservation.
