galloping Bobcat.
There are two possible sequences in which the feet touch the ground during lopes and gallops. If they land in a circular fashion—left front, right front, right hind, left hind—it is called a rotary lope or gallop. If the order does not circle the body but instead cuts across the body—left front, right front, left hind, right hind—then it is called a transverse lope or gallop. Rhythmically there is a three- or four-beat sequence for lopes, followed by a pause: 1, 2, 3, pause, 1, 2, 3, in which the number 2 is the overlapping strike of the second front and the first hind foot to touch down, or 1, 2, 3, 4, pause, 1, 2, 3, 4, pause, 1, 2…. Gallops produce a four-beat sequence, followed by a pause: 1, 2, 3, 4, pause, 1, 2, 3, 4, pause, 1, 2…Neither lopes nor gallops produce continuous rhythms, as are found in walks and trots.
When looking at track patterns on the ground, a lope typically becomes a gallop when both hind feet land beyond both front feet, but this is not always the case. If the order of tracks on the ground in a single set of four prints is front, hind, front, hind, then it is a lope. If the order is front, front, hind, hind, then it is more likely a gallop.
Similar to walks and trots, the placement of the hind tracks in relation to the front tracks betrays speed. As the pair of hind tracks moves beyond the pair of front tracks, this indicates a faster lope or gallop. Also note the distance between the groups of four tracks. In general, the longer the distance spanned by four tracks in a series and the shorter the length in between groups of four tracks (called the stride), the faster the animal is moving. At all-out speeds, some mammals will leave track patterns that look to the casual observer like trots, in that tracks are placed regularly and in a straight line. But each mark is a single track, rather than two.
Three particular lopes are characteristic of the mustelids, or weasel family. They are the 3×, 3 × 4, and 2 × 2 lopes. The 3× and 3 × 4 lopes are rotary lopes, in which a front and hind on the same side of the body may land in the same space, giving the impression of only three tracks in a set (the 3×), or land so that all four tracks are clearly evident (the 3 × 4). Hildebrand and Goslow (2001) show that weasels still have a front foot on the ground when the first hind foot touches down, and therefore this gait is a true lope.
A Fisher in a 2 × 2 lope.
The 2 × 2 lope is a transverse lope, although other than the order of footfalls it is very similar in body mechanics to the 3 × 4 lope. The same fluid arcing motion is used for both gaits. What is unique about the 2 × 2 lope is that the front feet pick up and the hind feet land directly upon the front tracks—creating a trail of paired tracks, where each set of two prints is actually a set of four, the fronts registering first and the hind feet registering directly on top of them. Meadow voles and smaller shrews also use this gait in deep snow. Based upon Hildebrand and Goslow's research on the 3 × 4 lope, we assume that a front foot is still in contact with the ground when the first hind touches down. Should we be wrong, then this gait would technically be a gallop.
Hopping and Bounding
The hopping and bounding gaits of rabbits and many rodents are different from lopes and gallops, in that the hind feet land and push off simultaneously, or nearly so. This is evident in the trail, because the hind tracks appear parallel to each other. Any local park should present ample opportunities to study squirrels using these gaits. Hops are similar to lopes, in that there is one moment when the animal is airborne during each cycle of footfalls, just after the hind feet push off. Bounds parallel gallops, in that there are two times when the animal is airborne during each cycle of footfalls—first after the front feet push off, and again after the hind feet push off.
The 3 × 4 lope of a Fisher in a dusting of snow.
The 2 × 2 lope of an American Marten.?
A hopping Snowshoe Hare.
A stotting Mule Deer.
The difference between the track patterns of hops and bounds is found in the relationship between hind and front tracks. When hopping, an animal's front feet land in front of the hind feet. Hopping is less common than bounding but can be observed in large voles, Muskrats, flying squirrels, and toads and frogs.
Hopping and bounding begin in the same way: the front feet either land as a pair (next to each other), or one after the other (one in front of the other), but in bounds the hind feet move forward beyond and to either side of the front feet. The front feet pick up as the hind feet pass to the outside, and there is a moment where the animal loses contact with the ground before the hind feet come down and push off again. This pushoff is followed by a second moment in the air, before the front feet touch down and the cycle begins again. Numerous species bound, including squirrels, chipmunks, and rabbits.
Stott or Pronk
An unusual gait used by Mule Deer, Pronghorn, Elk, and occasionally other mammals is the stott. In this bouncing gait, an animal pushes off with all four feet at the same time, and then lands upon all four feet simultaneously, or nearly so. Mammals moving in this way appear to be using pogo sticks. Although not as fast as the gallop, the stott is better suited to traveling quickly over broken terrain, as well as allowing an animal to respond to external stimuli more quickly and to change direction when its feet hit the ground.
The trail of a stotting Mule Deer.
The bipedal hop of a kangaroo rat.
Bipedal Motion: Gaits on Two Legs
Bipedal Hopping
Both hopping and skipping are saltorial motions in which the front limbs remain elevated off the ground, and the resulting track patterns include paired hind footprints. Few mammals use bipedal motion, and in California the most likely culprit will be a kangaroo rat or kangaroo mouse. Birds, too, hop and skip. In hopping trails, paired hind tracks appear right next to each other, or nearly so, and the gait is the typical kangaroo-style hop. This pattern is possible because both hind feet hit the ground simultaneously. Technically, feet would only truly hit simultaneously if the feet were placed exactly next to each other, or the animal were coming straight down. However, for our purposes we'll use the word “simultaneously” to mean at the same time, or nearly so.
