سنن النسائي

It was narrated from Ya'la bin Munyah that: a man from Banu Tamim fought with another man, and he bit his hand, so he pulled it away and a front tooth fell out. They referred the dispute to the Messenger of Allah, who said: "Would one of you bite his brother as a young camel bites?" and he thwarted it, meaning he judged it to be invalid.