Rise of the Mammals automata prototype. The dinosaur moves slowly up and down inspecting the shrew. The dinosaur is driven via via a reduction gear. The shrew is connected to a small cam on the handle drive shaft and twitches quickly up and down.

The main gear is based on the reduction gear box here and the dinosaur is a modified version of this model of an eoraptor.

There were some small mammals at the end of the age of the dinosaurs but I’m making no claims to the scientific accuracy of these characters!