This is possibly the best reason for children to have pets; to learn about the cycle of life, and about the value of grieving.

My mother died (killed by a doctor) when I was seven years old, and my siblings and I were shielded from the whole grieving process. One day she was there, the next day she wasn't, and the whole matter became a conspiracy of silence. Adults thought they were protecting us from grief, but in reality they were catalysing all sorts of narratives in our minds, because we simply didn't know or understand what had happened, and nobody was allowed to talk about it. The damage lasts forever. Proper closure is a critical part of life.