By Bob Humphrey
The sudden commotion of running steps on dry leaves startled me from my mid-afternoon daydream, and I quickly grabbed my bow as a plump doe raced by just out of range. A running doe could only mean one of two things. Either she'd been jumped by another hunter or, more likely, was being chased by a buck. I hoped for the latter, but she passed out of sight and sound with no escort.
It was several minutes later, and the woods and I were just beginning to settle down again when I heard another rush of footfalls, this time accompanied by an unmistakable grunting. The buck came at a full trot, nose to the ground, bird-dogging along the same route the doe had followed minutes earlier. He too passed by out of range, but it wouldn't have mattered anyway as his pace precluded any chance of a shot.
After I calmed myself, I pondered what I'd just witnessed and what struck me most was how precisely he followed her path, especially at such a rapid gait. She had long since passed out of sight and earshot. So, the only clues she'd left behind were tiny scent molecules, yet he followed them like a beacon in the night.
Deer communicate in several ways. Like us, they vocalize. But their vocal repertoire is extremely limited, consisting mostly of grunts, clicks, bleats and bawls that convey a few simple messages: I'm here. I want you or I need help. And they have big ears. But that's probably more to detect danger than for listening to other deer. They can also convey certain messages, such as dominance or submission, through body language.
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I contend, however, that scent is the most important means of communication for whitetails. On the transmission end, they have seven different glands or glandular areas (that we know of so far), all of which secrete different odorous compounds. And on the receiving end, they have a long nose crammed with convoluted surface area specifically designed for scent reception and detection. We really have no way of knowing, but various sources cite the whitetail's sense of smell being as much as 10,000 times stronger than ours.
Even though we are aware of it, we humans still sometimes overlook or underestimate the importance of scent to the whitetail. Sure, we go to great lengths to cover our own scent. We sometimes even try to communicate with, or at least attract, whitetails with their scents. We might feel like geniuses, but to the deer our feeble efforts are probably the equivalent of baby talk, or a child's first crayon drawing.
Consider that through the simple task of tending a scrape, a buck could be leaving a virtual Facebook of personal information. First, he addresses the overhanging "licking" branch with his forehead glands, leaving the same identifying scent as on the numerous rubs he visits. Then, delicately working twig ends into the pores just in front of his eyes, he deposits scent from his pre-orbital glands. Next he rub-urinates, dousing the ground with a rich stew of pheremone-laced urine combined with musky volatiles from his tarsal glands. Finally, he paws at the earth, grinding his interdigital glands into the ground, then scattering the malodorous soil across a wide area. It is factually based speculation, but in so doing he may very well be communicating his health, breeding status and quite likely individual identity to any deer that passes within smelling distance of the scrape, which for a deer, could be 100 yards or more.
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In future issues, we'll look more closely at how deer may use some of their other glands to communicate; but today's subject is the interdigital gland. In my humble opinion, it may be one of the most underrated, at least from a hunting perspective, and least understood from a biological perspective, the latter probably accounting largely for the former.
This much we know for sure: whitetails have four interdigital glands, one on each foot, between the toes (thus the name interdigital). They contain (and release) a yellowish, sebaceous material consisting of sloughed skin cells and glandular secretions called volatile fatty acids. These volatiles carry a fairly strong odor that is deposited on the ground with each and every step a deer takes. And they evaporate at different rates, which is how a deer knows which way to follow a scent trail. That is what I witnessed in the opening passage, and why deer tend to follow the same path as other deer that have passed by minutes, hours or even days earlier. We follow visual clues like trails worn in the ground, but deer are probably following olfactory clues left from the interdigital glands (and other glands) of other deer.
And those glands could be communicating far more than the fact another deer passed by recently. Dr. Jon Gassett conducted a sophisticated analysis of interdigital gland secretions and identified 46 volatile compounds from the interdigital scent. He also found that five of these compounds occurred in much greater concentrations in dominant than in subordinate bucks.
It is also widely speculated that interdigital glands may serve some function in alerting other deer to danger. We've all seen it. When deer sense danger but aren't exactly sure what it is, they sometimes stomp their feet. Is it merely the sound of a foot stomp that puts other deer on alert, or is the alarmed deer leaving an olfactory alarm? We don't know. But if you see this behavior and you stick around for any length of time, you'll probably notice that any deer coming close to where the alarmed deer stomped it's feet will also become edgy.
Maybe it's an overabundance of interdigital scent that puts them on edge. It's also possible the alarm stomps release additional compounds. When humans are alarmed, adrenaline surges through our bodies. It's likely the same occurs in deer, and perhaps some is released through interdigital or metatarsal glands, or both.
As previously mentioned, whitetails can communicate dominance purely through scent. Whether they actually do so intentionally is hard to tell, but the circumstantial evidence strongly suggests they do.
How can all this possibly help you as a hunter? Passively, look for well-traveled areas, just as you always did, the fresher the better. But keep in mind we see tracks. Deer smell them. And they'll smell you if you walk on the same trails.
Ever have one of those days when all the deer seem to pass by your stand just out of bow range? It may simply be that they're following the first deer that did so. If you're in a climber, consider moving your stand over, even if it's the middle of a hunt.
Actively, you can apply interdigital scent to boot pads. Several scent companies offer it. Use it as a cover scent when walking to and from your stand. Lay down a scent trail. The mere presence of interdigital scent may put deer at ease. Best of all, unlike most scents, which are rut-based, interdigital scent is timeless. You can use it throughout the season.
