Invasive species have traveled the globe with humans and found success in new environments. Unfortunately, their success has been at the cost of many native species. Invasives may out-compete natives, feed on native species, or spread disease to native populations.


Feral cats are considered an invasive species, especially in Australia and Japan, where they have caused the decline (and occasional extinction) of many small mammals, ground-nesting birds, reptiles and amphibians. They also carry infectious diseases that can spread to native animals, humans, and livestock.

Why do you think it is so difficult to control the spread of invasive species?