Allah Almighty says: "Then the compensation is the like of what he killed, from livestock." [Surah al-Ma'idah: 95]
Imam al-Shafi'i (may Allah have mercy on him) said: "And 'the like' (equivalent) means the like in description of the game that he killed."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / Q9892