Sayyiduna Abdullah bin Ja'far (may Allah be pleased with them both) relates: One day the Messenger of Allah (peace and blessings be upon him) seated me behind him (on his mount) and confided something to me in secret which I will not tell anyone. The narrator says: The thing the Messenger of Allah (peace and blessings be upon him) most liked to screen himself behind (when relieving himself) was a mound or a grove of date palms. So he (peace and blessings be upon him) entered the garden of a man from the Ansar, and there was a camel there. When it saw the Prophet (peace and blessings be upon him), it began to groan and its eyes shed tears. the Prophet (peace and blessings be upon him) went to it and stroked its back and the area behind its ears, and it calmed down. Then he (peace and blessings be upon him) said: "Whose camel is this?" A young man from the Ansar came and said: O Messenger of Allah! It is mine. He (peace and blessings be upon him) said to him: "Do you not fear Allah regarding this animal which Allah has made you the owner of? It has complained to me about you, that you keep it hungry and overwork it."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13790