Download the Locomotion System from the Unity Asset Store:
Go to Locomotion System at Unity Asset Store
Read my Master's Thesis about the Locomotion System:
Automated Semi-Procedural Animation for Character Locomotion
There is much more information about the Locomotion System on my blog:
Go to rune|vision blog entries with label locomotion
An older video demonstrating the Locomotion System at a slower pace. Features related to 4-legged animals are not demonstrated.