Wind! You’d lose the use of one ear most of the time if you didn’t.
A serious issue! Plus, it’s stylish, eh.
If you turn your head, you can hear even better, but you can’t always do that now, can you. You want to, like stand still.
All together now!
There’s no arguing with it. It’s a thing.
~
Skriðuklaustur
A Farm in Iceland 
Delightful!
They sure are! Very curious and affectionate people, those Icelandic horses!