What are the German researchers observing about rats and bats?

Researchers in Germany have observed invasive brown rats preying on bats in urban cave hibernation sites, using tactics like standing upright and plucking bats from the air.

How are the rats impacting bat populations?

Researchers estimate that even a small number of rats could kill thousands of bats in a single year, exacerbating the already significant pressures bats face from habitat loss, climate change, and disease.

Where else have researchers observed interactions between bats and rats?

At Tel Aviv University in Israel, researchers have observed Egyptian fruit bats strategically adjusting their foraging behaviors to avoid and even fight back against black rats that threaten their young.

Home / Science / Rats Ambush Bats in German Caves, Posing Threat to Urban Bat Populations

Rats Ambush Bats in German Caves, Posing Threat to Urban Bat Populations

9 Nov

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Summary

Rats observed preying on bats in German caves, including caching over 50 dead bats
Rats using different strategies to intercept bats in flight and target hibernating bats
Researchers estimate even a small number of rats could kill thousands of bats in a year

Rats Ambush Bats in German Caves, Posing Threat to Urban Bat Populations

In November 2025, researchers in Germany have uncovered a concerning trend of invasive brown rats preying on bats in urban cave hibernation sites. Mirjam Knörnschild, head of the Behavioral Ecology and Bioacoustics Lab at the Museum of Natural History in Berlin, was shocked to capture infrared footage of rats standing upright and plucking bats from the air, then crunching down on them.

Further investigation at another German bat cave revealed even more disturbing evidence, with researchers observing rats "patrolling the entrances and exits of the cave" and finding caches of over 50 dead bats that the rats had stored. Knörnschild and her team realized this was not an isolated incident, but rather an under-appreciated threat to city-dwelling bat populations.