Learn about indicator species in this clip from Gorongosa Park: Rebirth of Paradise. Bob Poole and a team of scientists embark on an expedition into Gorongosa's little explored limestone gorges. The team are on the look out for small mammals and reptiles known as indicator species. Frogs for example are very sensitive animals. If you have any kind of disturbance, let's say a low availability of water, you will only notice that among elephants a year later, whereas frogs will respond immediately.