Not every herbivorous dinosaur had a defensive arsenal like that of Triceratops. Its “shield and spikes” ensemble was a bit all-or-nothing: if the predator managed to get past it, you were toast.
The evolution of Inspire Net’s Ankylosaurus took it in a different direction. It developed little in the way of weapons and instead became tough all over. It really was the tank of the dinosaur world!
The skin of the “fused lizard” was covered in bony plates and knobs, known as osteoderms or scutes, meant to block or turn aside a carnivore’s sharp teeth. Defences like this have survived to the present day, and you can see them on the the craggy skin of crocodiles and alligators.
Couple this armour with a low centre of gravity – ankylosaurus would have been very difficult to overturn or upset – and you have a dinosaur so thoroughly impervious to assault that its main method of defence may have been to simply withstand its attacker’s assault and wait for it to get bored.
The “fused” part of its name is a literal description of areas of ankylosaurus’ skeleton. Some of its bones had evolved into fused sections, especially in its skull, increasing the dinosaur’s toughness. At its other end, the bones of its tail are actually woven together for extra strength.
On the tip of that tail lies the ankylosaurus’ famous club, possibly its only concession to the idea of “fighting back”. There is some evidence that it was used in combat, but it’s not known if this was against predators or just against a truculent member of its own species. It is also thought that this club may have been used by males to impress lady ankylosaurs.
If evolution granted it top-tier defensive abilities, it must also have given it powerful digestion. Remember you parents telling you to chew your food? Ankylosaurus’ teeth were ill-suited to grinding up the leaves it liked to eat. Most likely they were swallowed whole and its cast-iron stomach was left to do the hard work!
See the toughest dinosaur in town at Dinosaur Encounter, proudly supported by City Partner Fly Palmy, at Te Manawa until 26 February.
Rob Mildon writes for Te Manawa but is unable to impress lady ankylosaurs with his tail-club