Depending on the species, hedgehogs can have up to 6000 spines. The spines are modified hairs. They are hollow and made of a material called keratin. (Your fingernails are made out of the same material!)
When a hedgehog is born, it has a smattering of soft spines. These are hidden underneath a layer of swollen protective skin. The swollen skin soon shrinks to reveal the spines. Within a month, the soft spines are replaced with hard adult spines in a process known as ‘quilling’.
The hedgehog’s spines are defensive adaptation to protect it from predators. Most hedgehog species will roll into a tight ball if threatened, making it hard for its attacker to get past the spiky defences.
Hedgehog species with fewer quills (usually those found in warmer climates) are less able to defend themselves in this way, and are more likely either to flee from, or to attack, the predator.
The spines of a hedgehogs, are stiff hollow hairs, they are not poisonous or barbed and cannot be easily removed, they fall out naturally when a hedgehog sheds its baby spines and grows adult spines a process called “quilling”.