Horses Selective in Who They Copy
Whether a horse learns new behavior by copying another horse depends upon their social status, researchers in Germany have discovered. Horses can learn how to do something simply by observing another horse. But they'll only readily pick up the new behavior if they have a certain relationship with the horse they're watching.
The study at the University of Regensburg made use of horses adopting a "following behavior" towards people. One horse reacted to a handler in a riding arena and eventually responded by following the person around. Meanwhile another horse stood watching the whole event.
Then the bystander horse had a turn in the arena. If the horse they'd been watching was dominant in social status, the bystander quickly copied the following behavior.
Conversely, the bystander would not readily follow the handler if it had previously observed a subordinate horse. A horse also failed to mimic another horse's behavior if the horses were from two different social groups and didn't know each other.
Reference
Konstanze Krueger and Jurgen Heinze. 2008. Horse sense: social status of horses ( Equus caballus ) affects their likelihood of copying other horses' behavior. Animal Cognition. 11(3): 431-439.