While it may look similar to a hedgehog the tenrec is not closely related. In fact, recent DNA studies found that it is more closely related to the African elephant!
Its main form of defense is obvious- spines. When disturbed it curls up in a ball to protect its vulnerable head and belly so a predator is presented with a ball of spines. Luckily for mom, newborn tenrecs don't have spines at birth. The spines start to come in at 5 days of age.