Sahih Muslim Book 18, Hadith Number 4272.

Chapter : Stray thing found by anyone.

Zaid b. Khalid al-Juhani reported: A man came to Allah’s Apostle (may peace be upon him) and asked him about picking up of stray articles. He said: Recognise (well) its bag and the strap (by which it is tied) then make announcement of that for a year. If its owner comes (within this time return that to him), otherwise it is yours. He (again) said: (What about) the lost goat? Thereupon he (the Holy Prophet) said: It is yours or for your brother, or for the wolf. He said: (What about) the lost camel? Thereupon he said: You have nothing to do with it; it has a leather bag along with it, and its shoes also. It comes to the watering-place, eats (the leaves of the) trees until its master finds him.