It means they're about to eat you.
It means they are alert. listening. or paying attention. (if the ears are forward) If the ears are pointed back it can mean irritation or anger or fear.
A hamster will move its ears back when it feels threatened or is scared. This is one way of determining the mood of your hamster.
He is upset about something.
It's listening behind it or there's wind blowing in it's ears
having their ears pinned back is a horses way of showing aggrevation or annoyance. Unless there are flies, then they may be trying to prevent that. But mostly not a good thing when your horses ears are back
When a rooster gets on a hens back, he is breeding her. He pushes down on her back to bring her pelvis up so he can "shoot and score".
with the ears pinned back it sounds like she doesnt like it...
They are about to buck so watch out.
Depends on who you mean
Just tilted back ears is just a horse listening to something behind it. If they are pinned against the neck however, this would indicate anger or frustration.
I have never heard the saying, "Slap your ears back." However, I have heard of 2 others that are similar. "Pin once's ears back" means get ready to move or act quickly and decisively. "Box your ears" is a threat to hit someone in the face or head.
There are different degrees of 'backwards'. If his ears just flick back in a relaxed manner he is listening to something behind him. If his ears are pinned back flatter on his head he is sending a warning that he is not happy. It could result in a bite or a kick so when you see his ears like this be on your toes.