Researchers Uncover Alarming Rat Predation on Bats in Germany

Scientists have revealed shocking findings about the predation of bats by rats in northern Germany. In a research paper published in *Global Ecology and Conservation*, they documented how brown rats, specifically *Rattus norvegicus*, are hunting and consuming local bat species, including *Myotis daubentonii* and *Myotis nattereri*. This alarming behavior poses significant risks to bat populations, particularly in two critical hibernation sites.

Systematic Hunting Techniques

The investigation began in 2020, using infrared surveillance cameras to monitor the rats’ activities around the Segeberger Kalkberg, one of the key winter refuges for bats. Over five weeks, researchers recorded a total of 30 predation attempts, with 13 confirmed kills. The study also uncovered remains of at least 52 bats, suggesting a pattern of regular feeding and potential food hoarding by the rats. The findings indicate that the rats employ two primary hunting strategies: intercepting bats midair or ambushing them on the ground.

When attacking, the rats position themselves strategically to launch a quick and lethal bite. If the first attempt does not succeed, they use their forelegs to restrain the bat, delivering a second bite to ensure the kill. Follow-up studies conducted between 2021 and 2024 further documented rat predation at the Lüneburger Kalkberg, where researchers found a cache of bat carcasses arranged similarly to those at Segeberger Kalkberg, indicating a systematic approach to hunting by the rats.

Ecological Implications

The findings raise serious concerns about the ecological impact of rat predation on bat populations. Although brown rats are not natural predators of bats, they opportunistically consume any available food source. In different environments, such as near Japanese fish markets, their diet can comprise up to 86% fish. While bats may not make up the entirety of the rats’ diet, they could represent a substantial portion, exacerbating the threat to bat populations that are already under pressure from habitat loss and disease.

Bats play crucial ecological roles, providing essential services such as insect suppression, seed dispersal, and pollination. The potential decline of bat populations due to rat predation could disrupt these ecological functions, further impacting local ecosystems.

Moreover, the interaction between bats and rats presents a public health concern. Both species are known carriers of various pathogens, including coronaviruses. Although the study did not directly investigate pathogen exchange, the potential for disease transmission between these wildlife reservoirs is a critical issue that warrants attention.

The researchers emphasize the need for further investigation into these dynamics and their implications for both wildlife and human health. The alarming predation behavior of brown rats highlights the intricate and often unpredictable relationships within ecosystems. As the study unfolds, the safety of bat populations hangs in the balance, prompting urgent calls for conservation efforts.