Musnad Abu Ya'la al-Mawsili 160:50

Ishaq ibn Abi Isra'il narrated to us, 'Abdah informed us, from 'Abd al-Malik, from 'Ata', from Abu Hurayrah, from the Prophet (peace be upon him), who said: "Indeed, Allah has one hundred mercies. One is between mankind, the jinn, the wild beasts, and the vermin; by it they show affection to one another, by it they show mercy to one another, and by it the wild beast shows affection to its offspring. And He has delayed ninety-nine [mercies] with which He will show mercy to His servants on the Day of Resurrection."