Narrated Abu Hurairah: The Messenger of Allah (ﷺ) as saying: No retaliation is payable for a wound caused by a dumb animal, for a mine, and for a well. On the treasure found buried in the land there is a fifth. Abu Dawud said: A dumb animal means an animal which is free and has not tether, and there is no one (as a watchman) with it. It causes harm by day and not by night.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، وَأَبِي، سَلَمَةَ سَمِعَا أَبَا هُرَيْرَةَ، يُحَدِّثُ عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم قَالَ " الْعَجْمَاءُ جَرْحُهَا جُبَارٌ وَالْمَعْدِنُ جُبَارٌ وَالْبِئْرُ جُبَارٌ وَفِي الرِّكَازِ الْخُمُسُ " . قَالَ أَبُو دَاوُدَ الْعَجْمَاءُ الْمُنْفَلِتَةُ الَّتِي لاَ يَكُونُ مَعَهَا أَحَدٌ وَتَكُونُ بِالنَّهَارِ وَلاَ تَكُونُ بِاللَّيْلِ .
sunnah.com