This is about a 10 yr old dog ("Belker") who had cancer.
The vet who wrote this story told of going to the family's home to put the dog to sleep and out of its misery in its own home. The parents thought their 4 year old son (Shane) should witness the experience to help get closure on the family pet's death. After the euthanasia procedure, the vet wrote the following:
"We sat together for a while after Belker's death wondering aloud about the sad fact that animal lives are shorter than human lives. Shane, who had been listening quietly, piped up...'I know why'.
Startled, we all turned to him. What came out of his mouth next stunned me. I had never heard a more comforting explanation.
He said, 'Everybody is born so they can learn how to live a good life - like loving everybody and being nice, right?
Well, animals already know how to do that, so they don't have to stay as long. '