Up first we have the stegosaurus, a herbivore that lived in the late jurrasic period. It would weigh up to 6800 pounds; with plates on its back to observe sunlight to produce extra heat at night since it was a cold blooded reptile. What made this the most lethal weapon on the stegosaurs is the tail spikes. The spikes would be 18 inches long to hit predators. The predators for this herbivore is the allosaurs, the Ceratosaurus, and the Torvosaurus.Despite its size the Stegosaurus is beileved to be one of the dumbest dinosaur that was around, the brain was a size of a walnut.