I’m fascinated by track variation. No two tracks are ever exactly alike, even if they were made by the same animal doing the same gait on the same substrate. Sometimes variations within the prints of one species are so extreme that it’s hard to believe that they were made by the same kind of animal. This applies to all creatures, but I think the red fox is a particularly good illustration.
In the photo below you see a front print made by a red fox traveling from left to right. This is a typical track: oval in shape with finely pointed claw marks, and a curved impression–called a bar or chevron–running vertically through the middle pad. A striated texture in the toes and middle pad shows how the fur which covers the underside of the foot pressed into the mud.
The track pictured above also has some features that are found in all of our wild canines. There’s a dome in the center, and the major ridges meet at the dome to form an X shape. The toes are held tightly together and the claw marks point straight ahead.
Here’s another front print made by a red fox, again traveling from left to right but at greater speed. This time the mud was firmer, so the track is shallower and the marks of the hair are lighter. Instead of lying tightly together, the toes are spread and the claws, especially the inner and outer ones, angle outward. The bar in the middle pad is the deepest part of the track, suggesting that the horny protrusion might have served to increase traction.
A fox moving on even firmer mud and at even greater speed made the next example, again traveling from left to right. We see only the claw marks, the tips of the toes, and the middle pad bar. As in the previous photo the toes are spread and the claws angle outward.
Sometimes the fur on the underside of the foot is the most obvious feature of the track. In the next photo, made in wet mud, the direction of travel is from right to left, and the texture of the hair seems to cover the entire track except for the middle pad bar. But take a close look at the areas toward the tips of the toes, especially the two leading toes. There’s a spot in each toe impression that’s deeper and doesn’t have the striated texture. These marks aren’t just accidental artifacts–they’re real (although seldom seen) features of red fox tracks. Each toe has a small, hairless bump near its tip which can protrude through the hair to leave a mark.
There are other anatomical parts which can show up in tracks. The print in the photo below was made in soft sand by a red fox moving from left to right at high speed. The spread toes and deep toe and middle pad bar impressions should be familiar by now, but just behind and above the middle pad there’s an additional mark. This was made by the dew claw, the reduced fifth toe present on the insides of the front feet of most canines. And to the left of that and straight back from the middle pad there’s a shallow indentation made by the carpal pad, a knobby protrusion found higher up on the back of the front leg. This is another feature found on foxes, coyotes, and domestic dogs.
Dewclaws and carpal pads only show in tracks if the lower leg joint (it’s actually the carpal joint) is well flexed or the foot sinks down into the substrate. The print pictured above had some of both–the foot sank into the sand and the galloping gait caused significant flexion in the carpal joint.
I’ve been focusing on tracks in mud and sand because they show track details so beautifully, but snow can be just as revealing. The red fox that made the prints below was traveling from left to right. There’s a nice bar in the middle pad of the front track (at the lower left), and as we expect in the red fox, the rear track (at the upper right) has a smaller middle pad with no bar. The dome and canine X show clearly in both tracks. Small depressions at the tips of the toes of the rear track show where the hairless protrusions (the same ones seen above in the wet mud) pushed deeper into the snow. In dry, fluffy snow like the substrate in the photo below, the fur on the undersides of the feet doesn’t leave distinct marks. Instead it has the effect of blurring the outlines of the toes.
Track variants can be puzzling, but they can also lead to better understanding of foot anatomy and animal movement. So when you’re perplexed by an unusual print take a breath, focus on something different for a moment, and let the pieces of the puzzle fall into place at their own speed. It will be well worth your time.