Animal friendships are simply wonderful.
Our dog, Cheeky is good friends with a number of different dogs in the neighbourhood. Her very best friend is Conan, a beagle. Cheeky and Conan love to run together. When I take Cheeky out and say we are going to get Conan for a walk she immediately turns toward his house.
The family of a former student of mine has a great dog that adopted a baby crow one summer. Their dog found the crow at the edge of their yard. She wouldn't come in the house, but instead stayed by the baby crow guarding it. She 'took care' of the crow for the entire summer. The family taught the crow how to fly and their dog let her go by the end of the summer.
There are many stories of animal friendships out there. This video tells the story of Tarra and Bella, a dog and an elephant.