Lions and Tigers?  No, Beavers and Wolves

“Wolves (Canis lupus) and beavers co-occur across most boreal ecosystems in North America and Eurasia. Wolves are the primary predator of beavers wherever the two species co-occur, and beavers are important seasonal prey for wolves. Although wolves are primarily cursorial predators, they often use ambush strategies to hunt and kill beavers.