Ep. 507: Why Your Camo Pattern Matters Less Than What It’s Reflecting w/ Dr. Karl Miller (Part 2)

Beau Martonik sits back down with Dr. Karl Miller for the second half of their conversation, and this half is entirely about what a deer sees. Karl was part of the original work that got inside a whitetail’s eye to determine whether deer perceive color at all, and he later worked with Sitka on a camo pattern developed around deer vision rather than human vision.

He starts with the hardware. A deer’s pupil opens about three times wider than ours, which alone is roughly nine times the light-gathering ability, and a reflective layer behind the retina called the tapetum bounces that light back across the rods and cones a second time to roughly double it again. The pupil is a horizontal slit rather than a circle, and it rotates to stay level even when the deer drops its head to feed, so a deer eating acorns is still watching the horizon. They see roughly 310 degrees, whereas we see 120.

Then the tradeoff. Deer have no fovea centralis, they can’t accommodate for distance, and their visual acuity at a stationary object comes in somewhere around 20/40 to 20/60. Karl’s line is that they’d almost need corrective lenses to drive. What they do have is motion. Their eyes stay still and let the image travel across the retina engaging new cones, and they process that visual information roughly four to five times faster than a human does, which Karl suggests means your movement looks to them something like slow motion. That leads into a long back and forth on jumping the string, whether a deer is reacting to the sound at all, and whether it might be seeing the bow flex or even the arrow itself. Beau brings his axis deer footage from Hawaii into it, where the deer were on the ground before the arrow arrived at 25 yards.

The back half is camo, and it’s the most useful stretch of either episode. Karl lays out the two jobs camo has to do, explains why pattern detail matters far less than most hunters think and why outline and spectral match matter far more, and gets into whiteners and brighteners in fabrics and detergents that take ultraviolet light and re-radiate it into exactly the part of the spectrum a deer sees 20 times better than we do. He explains why he stopped wearing blue jeans in the woods, why a whitetail’s tail is white in the first place, why old army camo is actually good camo, and why a shiny fabric can beat you even when the color is right. He also walks through how Sitka’s Cover pattern was developed and what it was actually designed to solve.

He closes with what he calls the take home: hunt the deer’s brain first. There are only three questions in a deer’s head, and everything it does traces back to one of them.

Part one of this conversation is episode 506.

Topics:

00:00:00 — Part two intro

00:07:16 — A deer's eye is built for two jobs, and neither one is looking at you

00:11:32 — Pupil size, and nine times your light gathering ability

00:13:31 — Their eyes rotate to stay level when their head goes down

00:14:23 — The tapetum, and 18 times the light

00:21:21 — Blue cones across the whole retina, and 310 degrees of vision

00:24:49 — 20/40 to 20/60: they'd need corrective lenses to drive

00:27:39 — Flicker fusion, and why your movement looks like slow motion to them

00:28:40 — Jumping the string: the sound, the arrow, or the bow

00:34:29 — Drawing on a quartering deer, and why they don't look up

00:37:20 — What camo has to do, and what it doesn't

00:40:39 — Whiteners, brighteners, and camo that glows

00:42:53 — How Cover got built around deer eyes instead of ours

00:50:08 — Fabric shine, old army camo, and plastic blaze orange

00:54:03 — Hunt the deer's brain first

Dr. Karl Miller’s published research: Google Scholar, search “Karl Miller deer UGA”

Part one of this conversation is Ep. 506

The Wilderness Society - https://act.wilderness.org/a/26bcpledge-eastwest-1

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