OUTDOORS: Hybrid deer hard to spot

Whitetail deer live in Colorado but it is unlikely they will ever crossbreed with mule deer. (Courtesy photo/DJ Hannigan/via CPW)

Sometimes the best part of a hunting camp is the camaraderie between the hunters at day’s end. Many a world or political problem have been solved in these camps; too bad the politicians weren’t in camp to listen.

One particular camp that comes to mind was in Alabama, where we were in hot pursuit of whitetail deer in the heart of the southern rut. This particular evening, we were putting in overtime, led by several glasses of man’s best friend. One of the participants was a biologist for the Alabama Department of Conservation and Natural Resources in his real life. In camp, he was just another hunter who had not seen any deer yet.

The good biologist made a statement that eventually there will be only one deer species (between mule deer and whitetails) as evolution continues. He stated a pretty good case for hybridization between the two species.

Shortly after returning from Alabama, I left for a five-day mule deer hunt on the Eastern Plains of our fair state. We were fairly close to a small town called Deer Trail. On the second morning of the hunt, we stumbled upon a buck that had a beautiful 8-point whitetail rack, complete with brow tines, attached to a mule deer head, complete with mule deer sized ears.

We studied this odd-looking buck for quite some time. As he walked off, his tail was clearly longer than normal. The general consensus was this was a hybrid deer. He was the first I had ever seen in a long life of being in the woods.

When I got home, I locked myself into what my wife and I laughingly call my office and began making phone calls and doing research into the matter of hybrid deer. The results were not what I expected.

John Audubon in 1846 described the mule deer as “having fur like an elk, but hooves like a whitetail.” Other than those hooves, there are not many direct similarities between the two species. The scientific name for mule deer is Odocoileus hemionus, which means “deer that is half mule.”

In nature, different species of animals, even those that are closely related, are naturally kept from crossbreeding by being geographically isolated from each other. Those that live in the same habitat usually have much different breeding behaviors or rut at different times of the year to prevent hybridization.

Generally, this is true for mule deer and whitetails, but there are large areas where their ranges overlap. Eastern Colorado is one such place where the areas they roam are shared. Even the river bottom areas of Montrose and Delta see both species of deer cohabitating.

Identifying a hybrid in the field is a difficult task indeed. The difference between the two species is notably the tail, facial markings and ears. Each species has distinct characteristics and yet, regular genetic occurrences can cause an overlap of these appearances.

The only characteristic that can be accurately used in the field to identify a hybrid deer is the metatarsal gland, which is located on the lower portion of the rear legs. The metatarsal glands on a mule deer are 4 to 6 inches long and sit high lower leg, and always surrounded by dark brown fur.

The whitetail’s metatarsals are below the midpoint of the lower leg, less than 1-inch long, and surrounded by white hair. The hybrid deer will have metatarsal glands that split the difference in location, appearance, and length (2 to 4 inches).

Hybrids have been reported in captivity, dating back to the Cincinnati Zoo in 1898. During the 1930s and again in the 1970s, Arizona produced hybrids that resulted in 19 hybrid fawns, of which only eight survived the first six months.

Research has revealed that hybridization occurs in both directions; mule deer bucks with whitetail does and vice-versa, but by far the most common is whitetail bucks and mule deer does. This is because a whitetail buck is far more aggressive than a mule deer buck. A buck whitetail will run off any mule deer bucks during the rut, thereby leaving the opportunity for hybridization. I personally have seen a lone whitetail buck run off a herd of cattle just out of apparent meanness.

Scientists have been looking into hybridization for several decades. In genetic studies done in Alberta and west Texas, they have found hybrids can make up to 14% of a given population where the two species overlap, but a 6% proportion seems to be closer to the norm.

When a hybrid does make it to adulthood, it typically is not as well-adapted to the environment as the parent species. The hybrid, for example, does not have its escape the right way. Whitetails wag their tail, like a flag, as they gallop away. In contrast, a mule deer have a stot when they run, carrying them over shrubs and brush.

Research conducted by Susan Lingle in Alberta on captive hybrids has shown that stotting is so specialized to mule deer that hybrids cannot do it. She found the hybrids’ escape behavior was erratic because they approached the threat and jumped around in confusion. Such behavior is not likely to be passed on to the next generation since the first generation is unlikely to reach the age of maturity.

Occasionally, a hybrid will live long enough to breed, which further complicates identification. When a hybrid breeds with a mule deer or a whitetail, the offspring will even more closely resemble a full species, as the hybrid status becomes genetically diluted.

I did check in with Joe Lewandowski, formerly of Colorado Parks and Wildlife to get a take on Colorado hybrids and he had this to add, “Mule deer and whitetail hybrids in Colorado are rare in the areas the two species overlap. The rut behavior, timing of the rut and estrous cycles of the two species don’t normally line up. They can cross breed and produce offspring, but seldom do.”

Whitetail deer have made steady gains, both in territory and population growth, throughout much of the country over the last several decades. Mule deer populations, on the other hand, seem to rise and fall from one decade to the next. Lately, chronic wasting disease is taking a toll on mule deer. As the distribution of these species change, it alters the dynamic relationship between the two. Whitetails in the Rocky Mountain regions are expanding to the point that agencies are changing their regulations to take advantage of the abundance and allowing hunting/higher quotas for them.

Hybrids do occur and will probably continue to do so but I seriously doubt they will actually take over or merge to a single species. From being born in the first place, escaping the ever-present predator, and somehow reaching adulthood and breeding stage, will take a great deal of luck to happen.

Looking back, I am sure the buck we saw that day near Deer Trail was not a hybrid. He had unusual face markings and antlers, more of a genetic difference. Someday, I hope to actually get to see a real hybrid in the wild. It would be a rare occurrence.

Mark Rackay is a columnist for the Montrose Daily Press and avid hunter who travels across North and South America in search of adventure and serves as a director for the Montrose County Sheriff’s Posse. For information about the posse call 970-252-4033 (leave a message) or email info@mcspi.org

For outdoors or survival related questions or comments, feel free to contact him directly at his email elkhunter77@icloud.com

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