Meaning of the phrase "frog-walker" in reference to a horse

Question

The Marty Robbins song Strawberry Roan describes the story of a cowboy trying to break an old horse, the eponymous Strawberry Roan (I'm unsure of any connection to the various films of the same name).

There are three verses describing the horse (in negative terms emphasising his age and poor physical condition), and the attempt to ride it (emphasising his wild and untamed temperament), with the middle of the three acting as a transition between the two.

Down in the horse corral standin' alone
Is an old caballo, a strawberry roan
His legs are all spavined, he's got pigeon toes
Little pig eyes and a big roman nose
Little pin ears that touched at the tip
A big 44 brand was on his left hip
U-necked and old, with a long, lower jaw
I could see with one eye, he's a regular outlaw

I gets the blinds on 'im and it sure is a fright
Next comes the saddle and I screws it down tight
Then I steps on 'im and I raises the blinds
Get outta the way boys, he's gonna unwind
He sure is a frog-walker, he heaves a big sigh
He only lacks wings, for to be on the fly
He turns his old belly right up to the sun
He sure is a sun-fishin', son-of-a-gun

He's about the worst bucker I've seen on the range
He'll turn on a nickel and give you some change
He hits on all fours and goes up on high
Leaves me a spinnin' up there in the sky
I turns over twice and I comes back to earth
I lights in a cussin' the day of his birth
I know there are ponies that I cannot ride
There's some of them left, they haven't all died

(Lyrics from LyricFind via google)

I understand, or have been able to look up most of the terms, but the phrase "frog-walker" in the middle verse eludes me. Seeing as it occurs right at the transition, I'm not even entirely whether it's some sort of poor aged gait, or a reference to strong bucking (likening it to a frog jumping). The fact it occurs before a big sigh makes mean lean on the aged angle, but that the immediate next line talks about how near he is to being able to fly pulls me in the other direction.

Is this a known term describing horses (especially during rodeo or initial breaking), and how should it be understood?

Answer 1

It is a cowboy term for a horse that walks in a somewhat frog-like fashion in a series of short hops, which means the horse is unlikely to move too wildly and throw its rider. The term comes up in a few list of cowboy slang and books on cowboying.

Dictionary of the American West, Win Blevins, Texas A&M University Press, 1 Aug 2008, defines a frog walk as:

A form of mild bucking in short hops, not likely to throw a rider.

Another description is:

He could tell a great deal about a horse by how it came out of the pen and entered the arena ... a "frog walker" had short hops, which indicated it was unlikely to throw a cowboy.

Black Cowboys of the Old West: True, Sensational, and Little-Known Stories from History, Tricia Martineau Wagner, Rowman & Littlefield, 21 Dec 2010, p 11.

Answer 2

A frog walk is a type of hopping walk that a horse may do. Here are some examples from around the time of the song:

The horse objects to a saddle just as he does to thorny cactus on his back; hence the use of the colorful cack for saddle. On cold mornings practically all young broncos pitch a little or frog walk when first mounted. — Dialect Notes, 1939

Frog walkin' – in The Old Time Cowhand, 300, Adams says a horse that jumped about with arched back and stiffened knees was said to "frog walk" or "crow hop" — Arizona and the West, 1969

A horse that is fresh, particularly on a crisp morning, may indulge himself in a few antics when first mounted. When the game is mild and confined to a series of short easy hops, he is said to be doing a frog walk. — The Horseman's Book, 1973

Answer 3

Here, frog refers to the hind part of the underside of a horse's hoof. I haven't been able to find out what a frog-walker is, but I would guess that it refers to a horse that doesn't lift its hooves up properly when walking, so that the frog remains in contact with the ground for longer than is usual.

Updated to add: Laurel's answer, with some excellent quotes, makes me doubt myself now. Perhaps it does just mean walking jumpily, like a frog.