Do siblings have to be Rivals?

I wanted to throw a little spot light here about sibling rivalry and cooperations. I had a thought today as I was watching little Abraham being tickled by Jarom. First I have to explain, Abraham has been the most unusual about laughing, its not that he doesn't laugh but it is like he has a limited reservoir of laughter. It is not easy to reach that little reservoir but when you do he will laugh whole heartedly. The kids are always trying to find it and often they do. Here Jarom was holding the little turtle upside-down and had found that special spot by giving him the biggest 'bizerbert' Jarom could muster. Abe would curl his little body around Jarom's head and laugh.
So, as I was watching this I thought of all the times I had been mean to my own siblings when I was shorter. I also remembered all the present times when my own children are unkind to one another. I regret those times when I was not nice, especially when I knew what I was doing was hurting their feelings. I see the kids hurting each other both with hits and with words. This picture is a time, that does happen every so often, when a couple of my kids are having a great time. It is wonderful, I cherish these moments.