Toddlers Hitting Each Other
Is it normal for toddlers to hit their siblings?
Yes I believe it is. It is normal for the human to be a bit aggressive as they grow. When you see one being aggressive to another you can correct that behavior and get them to be less aggressive toward each other. This aggressive behavior is seen more in boys from what I have observed. Some do not show any aggressive behavior at all.
Yes, it is perfectly normal and even natural for toddlers to hit each other. They have not developed any proper sense of morality. Thus they act on their basic instincts. And it is the basic instincts of humans and most other animals to compete with each other. You can look at the hitting as not an act of malevolence, but rather one of playful competitiveness. Cubs do it, kitties do it, puppies do it, so it's natural for kids to do it too.
But the difference is that the other creatures are built for that sort of attitude while humans are not. Thus you must early-on enforce rules on the kids and teach them that hitting each other is not polite or productive. If not checked, this habit can result in a violent streak of nature.
By toddlers I assume we are talking about 1-4 years old. After that the child is aware enough to understand that hitting is wrong.
Getting a child beyond that age to stop hitting just by asking is another matter.
The best method of negotiation I find is to pose the question to them, how would they feel if someone was hitting them. Then say well, thats how it feels when you are hitting.