Hunters tend to overestimate a whitetail deer’s hearing abilities, maybe because we constantly–and mistakenly–marvel at their red-alert reactions to sounds we barely hear.

Those comparisons can be deceiving. For one thing, most adult hunters have abused their hearing for with decades of chain saws, leaf-blowers, hair dryers, lawnmowers, power-tools, deafening music and rifle blasts.

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In contrast, deer live in relatively quiet environments and don’t live long enough to damage their inner ears’ delicate parts. Relatively few bucks east of a line from Texas to the Dakotas live past age 3, and even less targeted whitetail does rarely reach age 10.

Hearing Tests
If you want more precise proof that deer hearing is superior, realize it’s challenging. Professor Karl Miller at the University of Georgia said it’s tough to scientifically assess how well deer hear compared to humans. People can sit in soundproof rooms, don headsets, and press a button or give a thumbs-up when detecting high- or low-frequency noises piped into their ears.

Deer aren’t so cooperative. In 2010, however, Henry E. Heffner and Henry Heffner Jr., a father-son team of audiologists who run an Ohio deer farm, created an audiogram that pinpointed the hearing capabilities of two female whitetails, which were 1- and 2-year-olds. The Heffners trained the deer to drink from a metal bowl, which they wired to give the deer a mild shock after “warning” them with sounds of varying volumes and frequencies.

The deer learned to quit drinking when hearing the sounds, and resume drinking when the sounds faded. The resulting audiogram revealed the deer’s hearing ranged from 0.115 kilohertz to 64 kHz, depending on the volume. Miller said the Heffner’s audiogram showed deer hear best in the 4 to 8 kHz range, which differs little from normal human hearing, which is best between 2 and 5 kHz. The tests showed that deer hear high-frequency sounds better than we do, but that humans hear low-frequency sounds better than deer do.

One of the deer’s hearing advantages, though, is its ability to work its two large ears independently to detect, direct and triangulate sounds from all directions. If their ears point away from the sound’s source, however, they can’t direct it into their inner ears. Human ears are fixed, of course, and the best we can do is cup a hand to an ear to capture more sound.

The Cocktail-Party Effect
Plus, we’re mere visitors to the deer’s world, where they live full time. Miller said the deer’s biggest audible advantage is probably in “neuro-filtering,” which might never be measurable. “That’s their ability to filter out sounds from background noise and give meaning to the sounds,” Miller said. “They’re much better than we are at hearing woodland sounds and knowing if it matters.”

In human terms, it’s like the “cocktail party effect,” in which our brain can focus on one voice while tuning out all other conversations except when hearing another voice mention our name, or utter words or phrases of special importance. And much as our ears can be overwhelmed by loud, sustained noise, a deer’s ears can be neutralized by high wind and heavy rain. If weather conditions are so severe that deer can’t rely on their eyes and nose to monitor their surroundings, they hunker down and wait things out.

Hunters, meanwhile, like just enough wind to rustle leaves and sway branches, which hampers a deer’s ability to hear coat sleeves snagging bark, arrows sliding across rests, or rattling antlers clicking on a hook.

Hunters also don’t want winds so brisk that distant bucks can’t hear grunt calls or rattling sequences. After that happened about 20 years ago to the late Gary Clancy, a veteran Minnesota deer hunter and outdoor writer, he recruited his daughter Katie, then 13, to assess how far sound carried from six different rattling devices.

Clancy’s ‘Unscientific’ Test
On a 75-degree day with 10 to 12 mph winds, Clancy drove to a large, recently cut hayfield. He gave Katie a walkie-talky and sent her off across the field while he monitored her distance with a laser rangefinder. She slowly walked while he rattled, stopping when she could no longer hear the rattling. As Clancy tested each rattling device, he continually “zapped” her with his rangefinder and recorded the distances.

The Clancys ran the tests with the wind and against it. The “Katie Clancy Rattling-Volume Test” revealed that rattling devices could, on average, be heard 512 yards downwind and 223 yards upwind; or 2.3 times farther downwind than upwind.

In his 2000 book “Rattling, Calling & Decoying Whitetails,” Clancy wrote: “No wonder that every accomplished horn-shaker I know cusses the wind.”

Of the rattling devices he tested, Clancy learned that calls shaped like antlers had audio that carried the furthest while rattling bags carried the shortest. Surprisingly (and not surprisingly), real deer antlers had the loudest volume.

No. 3 Defense?
Mark Kenyon, host of the “Wired to Hunt” podcast, said he respects the whitetail’s hearing, but ranks it third behind its nose and eyes in the deer’s defense system.

“They identify danger instantly with their nose, and they turn first to their nose to confirm things they see or hear,” Kenyon said. “I rank their nose highest, but I don’t shortchange their ears. You just have a little more room for error with their eyes and ears. You can’t be careless. I focus my energy on eliminating unnatural sounds, like anything metallic or squeaky. Deer won’t dismiss those sounds.”

Veteran deer hunter Judge Holdford goes a step further. Well, actually two steps. He considers the deer’s hearing its No. 1 defense mechanism, given that it can swivel its ears to listen in all directions. In comparison, deer can’t smell danger unless they’re downwind, and they have about a 60-degree blind spot behind them.

“Sound goes out in all directions and at all levels from the ground up, so deer are much more aware of us than we realize,” Holdford said. “They know how we sound when we’re walking, talking, driving in, parking or climbing trees. They don’t need to see us or scent us every time they hear us to confirm we’re out there.”

Holdford also thinks deer perceive danger in calls from birds and other wildlife. “Deer listen to crows and squirrels, and they really like pileated woodpeckers,” he said. “When a pileated woodpecker starts yacking, it lets the whole woods know you’re around. Deer tune into all those sounds. One time I watched a 3½-year-old buck bed down at dawn in a cutover, and basically snooze till about 8 o’clock. The only time he was alert was when two crows 150 yards away started yacking. He went on full alert for a half-hour, constantly checking the wind and listening with his ears. He didn’t relax until those crows shut up.”

Kenyon and Holdford agree, however, that deer are incredibly adept in pinpointing the location of distant sounds. “They have a remarkable level of spatial acuity,” Kenyon said. “If you’ve ever grunted or rattled in a buck, you know they can swivel those ears, pinpoint the sound, and eventually show up right beneath you or perfectly downwind of you. Eight out of 10 times they’ll come in downwind unless the terrain won’t allow it. They always know where that sound came from, and where to go to confirm it.”

Holdford had similar stories, including the time a big buck picked him off as he tried sneaking into a treestand by wading a swamp.

“If I can’t walk quietly to a stand, I won’t go in, so I decided to cross that swamp early, like 3 o’clock in the afternoon,” Holdford said. “But I flushed four wood ducks just as I approached the stand. I knew it was over. Any deer nearby would know something spooked those ducks. I took two more steps, got two steps up my ladder, and heard something 30 yards behind me. I turned and saw a really good buck standing about where those ducks flushed. He knew something was going on, and sneaked in and caught me.”

The Conundrum
Kenyon hates walking to a stand through dry or frozen leaves on calm days, but can’t decide whether it’s futile. “I’ve always debated that, and it always stresses me out,” he said. “Every step I take breaks a little part of me inside. I think every deer around hears me, so what’s the best option? Should I sneak as slowly and quietly as I can, or just get there quickly and get it behind me?”

Kenyon leans toward a speedy approach, but not in the steady, unbroken gait that’s uniquely human. “I try different paces and almost run at times,” he said. “Deer are used to hearing things crashing through the woods, and they know it’s not a sound or pace humans usually make. I’d rather be quiet, but that’s often not possible.”

Feature image via Matt Hansen.