A Study of Elk and Deer
One fall day when carnivore tracks were hard to find I began to look at deer and elk tracks more closely. If you are familiar with elk tracks you know that they are both larger and rounder than deer tracks. I decided to do a little study to determine whether there might be an empirical way to tell them apart. My hypothesis was that elk tracks would not only be larger but they would be relatively wider.
I set out to take measurements of as many deer and elk tracks as I could find over two weekends. I tried to select clear tracks of the front foot of different individuals as much as possible. I was successful in measuring 13 elk prints and 66 deer prints.
I present the results of my efforts in Figure 1. The diagonal line signifies a track with equal length and width, thus any track below the diagonal line is longer than wide. Clearly neither of my hypotheses were born out.
Figure 1. Plot of track width and length measurements for mule deer and elk.
First, I found that there was substantial overlap in the distribution of length and width for these two species. This should not have been too surprising since my sample included elk calves from that spring as well as large buck deer.
Second, I found that there was no obvious tendency for elk hooves to be wider than deer tracks relative to their length. I even confirmed this with a statistical test.
In conclusion, I am once again reminded that there is considerable variability in nature. Any application of simple criteria for distinguishing species is likely to have a substantial error rate. Elk and deer tracks are generally easy to visually distinguish in the field but this little study highlights the difficulties of trying to formalize those criteria.