It was narrated that 'Imran bin Husain said:"Ya'la fought with a man, and one of them bit the other, who pulled his hand away from his mouth, and a front tooth fell out. They referred their dispute to the Messenger of Allah and he said: 'Would one of you bite his brother as a stallion bites? There is no Diyah for that."
أَخْبَرَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنْ زُرَارَةَ، عَنْ عِمْرَانَ بْنِ حُصَيْنٍ، قَالَ قَاتَلَ يَعْلَى رَجُلاً فَعَضَّ أَحَدُهُمَا صَاحِبَهُ فَانْتَزَعَ يَدَهُ مِنْ فِيهِ فَنَدَرَتْ ثَنِيَّتُهُ فَاخْتَصَمَا إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالَ " يَعَضُّ أَحَدُكُمْ أَخَاهُ كَمَا يَعَضُّ الْفَحْلُ لاَ دِيَةَ لَهُ " .
Nesai
The Book of Oaths (qasamah), Retaliation and Blood Money • Hadith 4760