The Holy Prophet Muhammad, peace be on him, was Rahmatullil Almeen – mercy for all the worlds, his entire life is manifestation of great love and mercy towards all mankind as well as animals. Few examples of his mercy towards animals are presented below.
“He warned people against cruelty to animals and enjoined kind treatment to them. He used to relate the instance of a Jewish woman who was punished by God for having starved her cat to death. He also used to relate the story of a woman who found a dog suffering from thirst near a deep well. She took off her shoe and lowered it into the well and thus drew up some water. She gave the water to the thirsty dog to drink. This good deed earned her God’s forgiveness for all her previous sins.
‘Abdullah bin Mas‘ud ra relates: “While we were in the course of a journey along with the Holy Prophet sa we saw two young doves in a nest and we caught them. They were still very small. When their mother returned to the nest, not finding her little ones in it, she began to fly wildly round and round. When the Holy Prophet sa arrived at the spot he observed the dove and said, ‘If any one of you has caught its young ones he must release them at once to comfort it’ ” (Abu Dawud). ‘Abdullah bin Mas‘ud ra also relates that on one occasion they observed an ant-hill and, placing some straw on top of it, they set fire to it; whereupon they were rebuked by the Holy Prophet sa.
On one occasion the Prophet sa observed a donkey being branded on the face. He inquired the reason for this and was told that the Romans had recourse to this practice for the purpose of identifying high-bred animals. The Prophet (saw) said that as the face was a very sensitive part of the body, an animal should not be branded on the face and that if it had to be done the branding should be done on its haunches (Abu Dawud and Tirmidhi). Since then Muslims always brand animals on their haunches and, following this Muslim practice, Europeans also do the same.” (Life of Muhammad sa; p 372-373)