As Tuesday’s photo illustrated, horses can do things that look very strange—even frightening—to their two-legged owners.

The horse in the photo was yawning, but some owners will never see it happen.  That’s because most horses very seldom yawn.  The first time you see the behavior, you might mistake it for a seizure of some kind.  The horse’s eyes roll back, his ears flop, and he opens his mouth wide enough to let his tongue hang out.  The first time I saw a horse do that I was poised to run to the house and scream at my husband to “call the veterinarian!”  Luckily the horse closed his mouth, chewed a little, and wandered off.

A behavior not quite that strange is rolling.  If you own cats or dogs—and most horse-people do—you’ve watched your pet squirm around on the rug on his back, looking blissed-out or drugged.  It’s the only way most four-legged animals can scratch their backs.  Horses do it for the same reason—which is why most horses also enjoy a good grooming.  But sometimes their idea of beauty doesn’t agree with ours.  My idea of a beautiful horse is one that’s spotlessly clean, the long hairs on his muzzle are clipped, along with the hair on his fetlocks.  His mane and tail are free of knots, and his coat shines.  So what’s the first thing he does when you turn him loose in his pipe corral or stall?  Right.  He rolls. And grunts because it feels so good.  And then gets up and goes down again to roll on his other side.  Rolling is only dangerous if your horse does it near a fence and gets his legs caught under or between the rails, and can’t get up.  This horse is cast.  If he fails to free himself after five minutes, call a horse-savvy neighbor who knows how to help him.  Lacking a neighbor, do call your vet.  Cast horses can die.

Another thing a horse can do that might seem strange to you—especially if you’re on his back when he does it—is shake himself.  I’ve never seen my cats do it, but that doesn’t mean they don’t.  It just means I haven’t caught one in the act.  Dogs, especially wet dogs, shake.  Horses shake themselves all the time, often after they roll.  The movement begins with a side-to-side shake of the head, which travels down their neck, to their sides, and finally to their rump.  If you happen to be on your horse when he decides to shake himself, you feel as though you got caught in a blender.

There’s another odd behavior—odd to us because we don’t do it—called a flehmen response. As with yawning, some owners will never see their horse exhibit a flehmen response.  It usually occurs when a male catches the scent of a nearby mare who might be in season.  If I breathe into Gunsmoke’s nostrils, he usually curls his upper lip—I think he wants to know what I ate for lunch.  Although you couldn’t prove it by me, domestic cats will also exhibit a flehmen response, along with lions, tigers, buffalo, giraffes, and goats.

The only two behaviors you should worry about are excessive yawning, and if your horse gets cast.  In both cases, call your veterinarian.