Cats kill billions of animals annually according to a new Nature Communications study that warns of the environmental impact:

“We estimate that free-ranging domestic cats kill 1.4–3.7 billion birds and 6.9–20.7 billion mammals annually. Un-owned cats, as opposed to owned pets, cause the majority of this mortality. Our findings suggest that free-ranging cats cause substantially greater wildlife mortality than previously thought and are likely the single greatest source of anthropogenic mortality for US birds and mammals. Scientifically sound conservation and policy intervention is needed to reduce this impact.”

Nature Communications adds that cats, both feral and domestic, are responsible for the extinction of more than 30 species of birds and small animals.