Sahih Bukhari, Chapter: Jihaad (Fighting for the cause of Allah)

Abu Qatada went out (on a journey) with Allah's Apostle (SAW) but he was left behind with some of his companions who were in the state of Ihram. He himself was not in the state of Ihram. They saw an onagae before he could see it. When they saw the onager, they did not speak anything till Abu Qatada saw it. So, he rode over his horse called Al-Jarada and requested them to give him his lash, but they refused. So, he himself took it and then attacked the onager and slaughtered it. He ate of its meat and his companions ate, too, but they regretted their eating. When they met the Prophet (SAW) (they asked him about it) and he asked, "Have you some of its meat (left) with you?" Abu Qatada replied, "Yes, we have its leg with us." So, the Prophet (SAW) took and ate it.