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For the first time ever, brown rats have been caught on video systematically hunting down bats by stalking them and snatching them right out of midair. Scientists say this new development poses a serious problem, in more ways than one.
As most people are well-aware, rats are an invasive species that have wreaked havoc all over the world. Rat populations are growing out of control in many cities around the world and the problem is only going to get worse unless something is done about them. They are getting bigger than ever and are causing damage in places where rats have no business being present.
Now, brown rats, or Norway rats, according to a study published recently in the journal Global Ecology and Conservation, are becoming a threat to, of all things, bats.
“This study is the first to document systematic predation by Rattus norvegicus on bats at urban hibernacula hosting several thousand individuals in Europe,” the researchers wrote. “Using infrared video surveillance and thermal imaging at two major sites in Northern Germany (Segeberg and Lüneburg Kalkberg) used predominantly by Myotis species, we observed aerial interception and ground-based hunting strategies targeting swarming bats.
“The predation behavior highlights the remarkable manipulative abilities and behavioral plasticity of brown rats in urban ecosystems. Our findings suggest significant additional mortality risks for bat populations at mass hibernacula and raise concerns about potential pathogen exchange between two major wildlife reservoirs.”
In other words, these scientists used night vision cameras to capture video of rats attacking rats by grabbing them right out of midair. the resulting video is both incredible as well as more than a little bit frightening.
Rats killing bats is a problem not just for the bats
Scientists figured out that, based on the number of bats these rats killed during the years-long study, even a small colony of around 15 rats could kill close to seven percent of the roughly 30,000 bats that live in the cave in the winter. This definitely a problem for the bats, but it is also not great for humans.
If these rats continue to stalk and kill bats it could have an effect on their populations which perform “critical ecological roles and deliver substantial ecosystem services worldwide, including insect suppression, seed dispersal and pollination.”
There is also the issue of rats and bats both being carriers of numerous pathogens that are harmful to humans. The results of the study, the researchers wrote, “highlight a mechanism through which invasive rodent populations might contribute to the amplification and redistribution of pathogens within urban ecosystems.”
In other words, rats attacking bats could open up the door for a “potential pathogen exchange between two major wildlife reservoirs.” The scientists recommend “targeted control of these invasive rats” to not only safeguard vulnerable bat populations, but also to mitigate public health risks.