"Using swans to chase away geese is an effective practice, experts said, because swans are larger and territorial and will live in non-native landscapes. They're also not afraid to compete with other animals for resources. Swans, like many creatures, will defend their territory vigorously, especially when their young are involved, said Steve Sullivan, senior curator of urban ecology for the Chicago Academy of Sciences and its Peggy Notebaert Nature Museum."
The coelacanth was believed to be extinct until 1938 - one was found in the catch of a fishing trawler by a museum curator. This makes it a Lazarus taxon, a species that has 'risen from the dead,' thought to be extinct only to be discovered alive. The oldest fossil is 360 million years old, and it seems the fish has hardly changed since then. Many thought they went extinct 80 million years.