Furthermore, the Saint Bathans fossil species co-existed with the Saint Bathans mammal, suggesting that New Zealand wasn't devoid of land mammals when these bats first arrived. They give birth once each summer, to a single young. They are able to hibernate during the winter. In 2010 the Department of Conservation discovered a feral cat that was responsible for killing over 100 short-tailed bats over a seven-day period in a forested area on the southern slope of Mount Ruapehu.