Sunan an-Nasa'i 4410

It was narrated that Rafi bin Khadij said:"I said: 'O Messenger of Allah, we are going to meet the enemy tomorrow, and we do not have any knives.' He said: If the blood is shed and the name of Allah is mentioned, then eat, unlike (it is slaughtered) with teeth or nails and I will tell you about that. As for teeth, they are bones, and as for nails, they are the knives of the Ethiopians,; We acquired some spoils of war including sheep or camels, and a camel ran away, so a man shot an arrow at it an stopped it. The Messenger of Allah said: 'some of these animals' or 'these camels'- 'are untamed like wild animals, so if one of them goes out of your control, do the same." (Sahih)