This is a discussion on The Mare GLARE! Show your evil lovelies! within the Horse Pictures forums, part of the Horse Pictures, Videos, Artwork, and Contests category
Although I only have geldings, they definitely can act like mares!
Bart AKA my grumpy old man (He passed away this summer) learned it years and years ago when he was pastured with a bunch of mares.
Dozer didn't start making his stink face until he started getting pastured with my dad's draft consistantly (I think Bart taught Doz the face in an attempt to send Yuri a message) haha