Porcupines have quills.
First of all, they're called QUILLS! And it's to protect themselves.
no it does not use spikes to protect itself
Porcupines are rodents with spines (or quills as the are also known).
its a protection which animal have to protect itself from the predator...
to protect itself from creatures that could harm it.
Quills
i think so; otherwise the quills would not hold on
Yes, hedgehog quills are modified hairs.
The correct name for the spines of the echidna is "quills." These quills are modified hairs that provide protection against predators. Echidnas use their quills as a defense mechanism by curling into a ball, making it difficult for attackers to get to their soft underbelly.
A cactus adapts to its environment by losing its spines to reduce water loss and protect itself from animals.
Spines IS the correct term when referring to the echidna. The questioner is probably looking for the answer "quills", but this word is usually used in reference to the porcupine. Echidnas and porcupines are not related at all. Therefore, echidnas have spines and porcupines have quills.
So that the sea urchin can protect itself from is enemies, it also has venomous spines. They also use their spines to kill other sea ceatures, so they can eat them.