• Horns, Claws, and Spikes - Many dinosaurs had deadly, knife-like protuberances that were excellent protection from being eaten (for example, Triceratops and Kentrosaurus). Some sauropods had large thumb claws; these were especially prominent in the young and in juveniles.
• Large size - Some adult diplodocids (like Apatosaurus, Diplodocus, Supersaurus, etc.) and other dinosaurs were so large that only the hugest carnivores or packs of carnivores were a danger.
• Armored plating (bony plates fused into leathery skin) - Ankylosaurids (like Euoplocephalus, Ankylosaurus, and Sauropelta) were plated all over the tops and sides of their bodies. Even their eyelids had armor plating. Only their underbellies were unprotected. To kill an Ankylosaurid, a predator would have had to flip over a terribly heavy animal over - not an easy job.
• Thick, leathery skin - This would provide only a little bit of protection from predators with sharp, strong teeth like T. rex, Giganotosaurus, and Utahraptor.
• Head butting - Pachycephalosaurs (like Pachycephalosaurus, Stegoceras, Wannanosaurus, etc.) and other thick-skulled dinosaurs may used head butting to repel predators.
  
  It had long been thought that Pachycephalosaur's thick domes may have been used for ramming rivals during mating and dominance combat, for attracting mates, and as a last-ditch self-defense against predators. Paleontologist Mark Goodwin of the University of California at Berkeley has analyzed many pachycephalosaur skulls (including those of Pachycephalosaurus), finding no evidence of healed scars. Also, under close analysis, the thick skull bone is not rigid and solid, but porous and fragile when put under extreme pressure. ``It's time to kill the myth ... It certainly wouldn't be in their own best interests to ram heads in a fight,'' said Goodwin ``They would have killed each other, and a couple of bowling balls would hardly make good targets.''
• Speed - Leaving a fight can be easier and safer than fighting.
• Bludgeon-like tail clubs - Ankylosaurids (like Euoplocephalus and Ankylosaurus) had bony tail-clubs that could easily have been used for defense, which would have been useful for these lumbering, plated grazers. Also, some theropods, like Shunosaurus, Omeisaurus and maybe Mamenchisaurus had tail clubs for protection.
• Whip-like tail - Some people believe that sauropods may have used their massive tails as a whip to lash at their attackers. This theory seems unlikely given the amount of physiological damage to tail tissue that would be caused by the sudden acceleration near the end of the tail (and the deceleration upon impact). Also, the large sauropods probably grazed on tree leaves, giving them no room to whip their tail around without hitting tree trunks and getting severe tail damage.

DINOSAUR DEFENSE ACTIVITY

• Dinosaur defense printout