Miacis was a small mammal, one of the first carnivores. It had sharp teeth to kill its prey. It had a long thin tail for balance as it climbed trees. It was probably dark colored to blend in with the forest.

Cyanodictis was a smaller carnivore. Its small size allowed it to hunt the rodents and lizards that the larger dominant carnivores ignored. They also had longer noses to dig for smaller prey.

Tomarctus was a scavenger with a strong jaw. It probably used the strength in its bite to break the bones of animals left dead by larger hunters. It would eat the bone marrow, the most nutritious part of the body.

The Gray Wolf is the oldest species and all of the dog breeds in the world are descended from the wolf.