It's easy to tell, when you see the comparisons above, which elephants are relaxed and which are in a defensive mode.  The ones in a defensive mode are so because people - that would be me - have come too close to them and their young.  If you listen to their warnings and back off, you can enjoy hours of entertainment watching the little ones play.  For a great deal of time I watched the herd in the photo on the far right  - which consisted of a young bull - the one with his head in the dirt - bully his sister and cousins by pushing them in the river and butting them in mock practice charges.

I watched the below wildebeest being born by complete accident.  I was watching rhino when I heard a noise and looked over just as the calf dropped.  Within three minutes the baby was up and walking albeit on shaky legs.