Many people often wonder whether porcupines can shoot their prickly quills like darts when threatened?
The answer is, No; this is an absolute fallacy, probably originating because predators are sometimes found dead or alive with quills sticking out of various part of the body, or quills are found lying on the ground.
A logical assumption would be that the predators harassed the porcupine, which retaliated by firing its quills as defensive weapons. Make no mistake, they are very formidable defensive weapons, but cannot be released at will and fired.
What are porcupine quills?
The quills are modified hairs, present from birth in a softened state.They vary from thin, relatively soft hair-like structures on the head and shoulders to more typical hard & robust structures that are situated on the rest of the upper body and tail. They are hollow structures, randomly banded black and white that signal danger - the classic nocturnal warning (oposematic) colours.
Used as defense against threat
When confronted, the porcupine will turn its back to the aggressor and rattle its quills by stamping the feet, the hollow resulting in a remarkably ominous sound obviously designed to deter attack. While this happens, the porcupine makes short backward rushes in an attempt to jab the enemy with quills. They are often successful, driving the quills in deeply. These structures are very similar to the central vane of a bird's feather and bend rather than break easily. This toughness allied to the sharp point enables the quills to penetrate quite deeply, and as the animals retreat, the quills are easily pulled loose from the skin.
Predators will often persist in numbers and driven by hunger, they will succeed in killing the porcupine. This is usually done by securing a hold on the head, which is without quills,and then flipping the porcupine over to get at the soft unprotected throat and belly. The costs are sometimes not worth it, however; eyes are blinded or quills are driven deep into necks, mouths, or paws. The quills are not always successfully removed, particularly if the animal is a loner. It is likely, then, that the quills would be dirty and would infect wounds. This scenario often leads to death.
Porcupine quills shed naturally, and also come loose in inter and intra-specific confrontations; and this is how one comes to find them on the ground.