Sahih Muslim | Book 7 | Hadith Number 2724

Narrated by Salim
Salim reported on the authority of his father (Allah be pleased with them) that the Apostle of Allah (may peace be upon him) said: Five are the (beasts) which if one kills them in the precincts of the Ka'ba or in the state of ihram entail no sin: rat, scorpion, crow, kite and voracious dog. In another version the words are: "as a Muhrim and in the state of ihram".