Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: The wound caused by an animal is pardoned, the blood of one who dies by falling into a well is pardoned, and there is a fifth (one-fifth zakat) in buried treasure.
Hadith Referenceالمنتقى ابن الجارود / كتاب الزكاة / 372