A few possible answers:
Armadillo
Millipede
Snakes
Dogs protect themselves from danger in a couple of ways. One way to is to curl up and become submissive, and small. Another way is with their barking and growling. They do this to scare away danger.
armadillos curl up in to a ball ( their shell protects them) they are slow and the anaconda to fast for the armadillo to run
they curl up in a ball
They curl up into a ball and either stay there or they will ram into the opponent.
Hedgehogs have spines to protect themselves from predators and threats, when threatened they curl into a ball with their spines sticking out.
To protect themselves and sometimes to antimidate their enemys
Ferns curl up to protect themselves from harsh conditions like extreme heat or lack of water. This helps them conserve moisture and survive in challenging environments.
they curl up to protect other animals such as ants from taking their food - Anna Jones
They curl up in a ball so all their quills are out and make loud hissing noises
I had never seen centipede curl up if disturbed. Milipedes do curl.
When they are in danger,(They are tryi ng to stay safe) They would probably find the nearest rock or reef to curl up in and camoflauge from the predator. ^_^ Hope that helped. Cheers~ xD
They are insectivores (the eat insects). Their spikes are made of the same material as hair and nails. They can curl into a ball to protect themselves from predators.