 In isolated landmasses , such as Australasia , there are often no other native , medium @-@ sized quadrupedal predators ( including other feline species ) ; this tends to exacerbate the impact of feral cats on small native animals . Native species such as the New Zealand kakapo and the Australian bettong , for example , tend to be more ecologically vulnerable and behaviorally " naive " , when faced with predation by cats . Feral cats have had a major impact on these native species and have played a leading role in the endangerment and extinction of many animals . 
