1. In Search of Quills
Get the Point?

2. Porcupine
The Quill Pig

3. The Quill on the Porcupine

4. Unusual Trait of Porcupine
Of course, the most famous characteristic of this animal are the quills. When a porcupine is threatened, it assumes a defensive posture—head and shoulders lowered, back to the threat, every quill erect, tail thrashing back and fourth. This is usually enough to scare away any would-be predator. Quills come out of the porcupine's skin easily, but they quickly become embedded in the enemy, working their way in deeper and deeper. Not only is this painful, it can be fatal. 

5. Close-up of Quill

6. Porcupine is in the Rodentia Clade

7. Rodentia
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing.

8. Mammal Clade
Monotremes

9. Mammal Clade
Monotremes

10. The new world porcupine is not the only animal with quills

11. Echidna

12. hedgehog

13. Spiny tenrec

14. Old world porcupine