The porcupine (porc = pig + pine = spine) or porcus spinosus (spiny pig) lives in Africa. It is like a hedgehog, with spines or quills on its back. It can shoot its quills to wound a dog that is chasing it. It hibernates in winter. It is strong both on land and in the water.

By these are signified the heretics who are produced in the persecution of the church; when indeed the church has peace, they hide themselves in secret. Let them lie in wait to snatch away the poor man who lacks the gold of faith. But the prickly ones [hispidi] are heretics with sharp arguments, by which they kill those who approach them. - [Thomas of Cantimpré, Google-assisted translation]

Porcupines cannot shoot their quills; they come loose and penetrate on contact, as many a foolish dog will attest.