سنن ابن ماجه

It was narrated from Abu Sa'eed Al-Khudri that: The Prophet (ﷺ) was asked about the water basins located between Makkah and Al-Madinah, which were visited by wild animals, dogs and donkeys, and about using them for means of purification. He said: "Whatever they (the animals) have carried in their bellies is for them, and whatever is left over is for us, and is pure."