Beaver

Date of disappearance: Mid-late 18th Century at the latest
Reason: Hunting
Special power: Beavers create habitats that allow hundreds of other species to return and flourish. They slow the flow of rivers, reducing the danger of flooding. Young salmon grow faster and are in better condition in areas where beavers live.
Status: Beavers have been successfully reintroduced to Knapdale in Scotland. Unofficial populations are thriving in the River Tay and its tributaries. They have also become established in the River Otter in Devon. The re-establishment of beavers has widespread public support.