The Marvels and Mysteries of Deer Tracks

When we think of deer tracks what usually comes to mind are heart-shaped prints like the one shown in the photo below. The paired toes together form the overall shape, and the pointed ends of the toes point forward. In tracks like the one in the photo, the ridge that runs front to back between the toes may be as important for identification as the toes themselves. In fact, the tell-tale ridge may still be visible even when most other track details have been destroyed by weathering or melting.

The specialized feet of deer are very different from those of their ancient five-toed ancestors. The two large toes that make up the print in the photo above are analogous to the third and fourth fingers of our hand, but the toe bones (analogous to our finger bones) are highly modified and are enclosed in tough, protective structures. There are two smaller toes, the dewclaws, which are analogous to our index and pinky fingers and sit higher up on the back of the leg. The innermost toe (analogous to our thumb) was completely lost in the course of evolution. You can see the arrangement of the large primary toes and the smaller dewclaws in the next photo of the front feet of a deer.

Photo from Deeryproof

Deer hooves are superbly adapted for running and jumping. Their keratinaceous outer sheathing combines with resilient internal tissues to cushion the feet against impact. The dewclaws don’t touch the ground most of the time, but with faster movement or on softer surfaces they can make contact to provide more support. In the next photo you see tracks made by a deer moving toward the right on a relatively soft substrate at a slow gallop. There’s a front print on the left and a hind print on the right. In each track the marks made by the dewclaws sit behind the impressions of the large main toes. (You’ll notice that the dewclaws of the front foot are angled to the sides while those of the rear foot are pointed more to the front.) The feet of deer are small relative to the animal’s size and bear more weight per unit area compared to non-hoofed mammals. This is why deer tracks show up on surfaces that are too firm to reveal the traces of most other animals (a serendipitous side-effect for trackers). It’s also why deer tracks are usually deeper than the tracks of animals like coyotes and bobcats, and why deer are generally less stealthy than mammalian predators.

You can see from the photo above that the two large toes are not always held tightly together the way they are in the first image. Sometimes a “four-toed” deer print can take on a bizarre appearance. In the next photo you see a hind track which has a resemblance to the bounding pattern of a squirrel. The tips of the large toes appear rounded because their points pushed downward under the soil surface.

Here’s an image of the front track of a rapidly accelerating deer in which only the marks of the dewclaws and the tips of the large toes registered.

Even when the dewclaws don’t touch the ground the two main toes may be separated, as in the photo below of a hind foot. Deer can exert muscular control over their toes and are able to spread them when they need more support or stability.

Here’s another shot of a rear track, again with the toes separated.

In the next photo you see some deer tracks I found on a seldom used railroad line. The animal had first walked through some mud and then travelled along the railroad track. It stepped carefully on the ties, and wherever it stepped it left muddy impressions. In the photo the direction of travel is from top to bottom, and what you see are the edges of the hooves printed in mud on the wooden ties. There are two tracks partly superimposed, the front print a little ahead of (below) the rear print.

If the tracks in the previous photo are hard to understand, the next image may help. There’s a front track (at the upper left) and a rear print (at the lower right), and the direction of travel is toward the upper left. The firm sandy base prevented the deer’s hooves from sinking in, and the thin covering of loose sand recorded the track details nicely. The outer rims of the hooves show as curved grooves in the sand, but the inner parts of the hooves barely touched the surface.

Tracks like these are sometimes misidentified as bird tracks, so beware! In fact it’s important to always be fully engaged–even with deer tracks–because, as the preceding photos show, they don’t always conform to our expectations. Every once in a while, among all the typical prints, you may find some that are surprising or puzzling. If you spend some time on these, you’ll gain a deeper understanding of deer tracks, both the common ones and the not so common ones.

Deer Browse

Signs of spring are all around us, but there are still some interesting discoveries to be made about the past season. Early spring is a perfect time to learn about the winter diet of white-tailed deer. We may think that deer are basically grazers as we see them placidly feeding in fields, like cows and horses. But that would be wrong. Cows, horses–and bison, to include an example of a wild species–are strict grazers and consume grasses, forbs, and other non-woody plants year-round. Deer are browsers rather than grazers. Although they feed on the same kinds of low-growing vegetation as grazers during the growing season, in winter they switch to the twigs, buds, and bark of woody plants. The deer you see in the lead photo (not my shot, but I couldn’t find a good attribution for it) are eating the twigs of a cedar sapling.

Deer do not have upper incisors, so in order to remove a twig they clamp it between their lower incisors and their tough upper palate. A jerk of the head suffices to yank the twig off, enabling it to be macerated by the molars and then swallowed. Rough breaks like those shown on apple in the photo below indicate that deer were feeding on the small twigs.

This contrasts with the sign left by rabbits and hares, which also depend on woody browse for winter food. Rabbits have both upper and lower incisors, and they make sharp, angled cuts like the ones shown in the next photo of multiflora rose.

The browsing preferences of deer vary in different regions. Some of their favorites in the northeast are sugar maple, ash, dogwood, striped maple, northern white cedar, and hemlock. In the next photo you see a sugar maple branch that was browsed by deer. The animals are not equipped to chew on larger branches, so they limit their browsing to the small twigs and buds at the branch tips. In mature forests these only become available if trees or large branches fall, which is exactly what happened in this case.

Hungry deer will eat everything they can reach, and unrelenting feeding often leaves browse lines like the one on northern white cedar in the photo below. This doesn’t affect the overall health of the stand, but browsing can have adverse effects on the growth of smaller trees.

The ash seedlings in the next photo show the excessive lateral branching patterns that result from heavy browsing. During each growing season the young trees form new twigs and buds, but each winter the new growth is eaten by hungry deer. The stunted trees are never able to outgrow the reach of the deer and eventually die.

Deer found a hemlock sapling at the edge of a field, and you see the result in the next photo. It’s hard to see the hemlock against the background because so many of the small twigs have been eaten, but if you follow the main stem up from the bottom center of the photo you’ll see how much foliage is missing.

Overbrowsing makes a difference in the appearance of forests. In the next photo you see a woodland that has been heavily impacted by winter deer feeding. The lack of understory trees makes it easier to walk through this kind of forest, and its cleaner appearance may be more appealing. But this forest is in trouble.

In the next photo you see a much healthier woodland. The spaces between the large trees are filled with young and medium-sized saplings, and these are the ones that are ready to fill gaps when larger trees die or fall.

Without a multi-aged understory, forests have limited ability to regenerate. When large trees die, there are no young trees ready to fill in the gaps. It’s true that there are seeds in the soil that will germinate quickly once openings are formed, but the delay in regrowth may allow invasive species to get a foothold. Signs of deer browsing tell us much more than the mere presence of hungry animals. There are larger lessons to be learned, and nature is ready to share them if we are willing to pay attention.