In northern Germany, researchers have filmed brown rats (Rattus norvegicus) leaping from cave ledges to catch bats mid-flight — the first evidence that rodents can intercept flying mammals. The finding, published in Global Ecology and Conservation, turns one of ecology’s everyday characters into an unexpectedly agile predator.
The behavior was recorded at Segeberg Kalkberg, a limestone cave that shelters around 30,000 hibernating bats each winter. Using infrared video over five weeks in autumn 2020 and thermal cameras from 2021 to 2024, a team led by Florian Gloza-Rausch in Bad Segeberg captured footage that’s unusual, for sure: a rat balancing on its hind legs at the cave entrance, sensing the movement of wings in the dark, then springing up to seize a bat from the air.
Across five weeks of monitoring, the researchers confirmed 13 kills and found a hidden cache of 52 bat carcasses — clear signs that the rats weren’t scavenging leftovers but hunting deliberately. At that rate, a small group of rats could wipe out about 7% of the bat population in a single season.
That’s remarkable for an animal not built for flight or pursuit. Brown rats are omnivores that typically scavenge or prey on slow-moving targets. Yet here, they appear to have developed two hunting strategies: aerial interception at the cave mouth and ground attacks on bats crawling to roost. How the rats locate their targets in near-darkness isn’t fully clear, but researchers suspect they use whisker and hearing cues rather than sight.
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The study describes this as unexpected behavioral plasticity in brown rats. The researchers believe the dense streams of bats and the narrow cave geometry created the perfect ambush zone — a place where a patient predator could learn a new trick.
The discovery also adds a new stressor to European bat populations, which are already under pressure from habitat loss and disease. Because brown rats are invasive across much of the continent, their access to major hibernation sites could have lasting ecological effects. The authors suggest managing rat presence near large roosts as a precaution.
Nevertheless, the most compelling part of the finding lies not in its numbers but in its image: a common city rat, usually seen raiding bins, now standing alert in a cave mouth, hunting with precision that blurs the line between scavenger and specialist. It’s a reminder that adaptation doesn’t always unfold in distant rainforests — sometimes it happens under our own streetlights, in ways no one thought to look for.
Story Source: Gloza-Rausch et al. (2025), published in Global Ecology and Conservation. Read the study here.