How The 2017 Solar Eclipse Will Impact Deer Behavior

AJ Gall

By now you know we are in for quite a treat on Monday, August 21 as a total solar eclipse will cast shades of darkness across much of the U.S.  This sudden onset of darkness during the day could cause some confusion across the animal kingdom, especially since most animals rely on cues from the sun or the moon to keep their biological clock in check.  With this once in a lifetime event, there comes a lot of questions and uncertainty, many of which revolve around how wildlife will act given this surprise event.

Will Any Animals Be Affected by the Total Eclipse?

Most large mammals won’t show a noticeable change in habits from the sudden, unexpected dose of darkness, but some birds, insects, reptiles, and amphibians sure will.  As you can imagine, many birds will retreat to their roost sites, become silent during eclipse totality, then begin their morning melodies as the sun reveals itself again.

Insects like grass hoppers and cicadas may go dormant, while others like mosquitos and crickets might become briefly active. Same can be said about different types of frogs, and reptiles.  Don’t forget, the disappearance of the sun also brings a drop in temperature (Brrrr…better grab a flannel), which can impact cold blooded animals. However, the duration of the eclipse is likely too short to notice any behavioral changes.

Bottom line is, total solar eclipses don’t or haven’t happened enough to have sound scientific data at this day in age.  Most accounts of changes in animal behavior during eclipses are simply observations. One cool way you can help the science community is to document any eclipse-related animal behavior through the Life Responds project on the iNaturalist app. You can download the iNaturalist app on the App Store or Google Play.

Photoperiod Rules Deer Activity

No, the solar eclipse won’t spark an early onset of rutting behavior, or cause a buck to shed its antlers early, but if you want to understand how important the sun is to a deer’s daily and seasonal habits, just check out the annual Rut Predictions. It’s no stretch to say the sun controls most major physiological changes deer go through on a seasonal basis – at least for deer north of the 35th latitude.  In short, photoperiod (the amount of daylight) triggers hormonal cues in deer, which in turn regulates testosterone levels in bucks and estrogen levels in does.

This curve represents how testosterone levels (controlled by photoperiod) trigger changes in deer behavior.  The peak of the curve is the rut.

The rut, velvet shed, and antler shedding are just a few major changes triggered by changes in photoperiod.  This is precisely why most would argue (and science shows) the rut occurs the same time every year, along with antler and velvet shedding – again, this pertains to deer in the northern U.S.

Remember August 21st when Checking Trail Cameras

As a deer hunter, one might hypothesize the total eclipse event on August 21, 2017 might spark an increase in average daytime movement.  The reason being that deer are crepuscular animals, meaning they are primarily active during dawn and dusk.  It’s likely some universities will compare whitetail tracking collar data after the eclipse to see if there was any correlation and we’ll be sure to share the results if they do.  However, chances are the duration and suddenness of the eclipse will prevent any noticeable behavioral changes.

Deer hunter checking trail cameras

As someone with a handful of trail cameras, I’ll be interested in seeing if there’s any noticeable shift or increase in activity triggered by the total eclipse.  Could you imagine if the total eclipse happened during bow or gun season?! If deer activity proves to increase during totality, that may be a day to schedule hunting vacation around. Plus, then you could watch the total solar eclipse from your treestand! My luck, a giant booner buck would walk by right at the moment of total darkness.

Wishing everyone a safe and Legendary viewing experience!

Legendary Whitetails | Buck Camp Flannels

About The Author
From Woods to Table

AJ Gall

AJ Gall's prior hunting and wildlife experiences began long ago and make him the perfect contributing deer hunting guru.  As a habitat consultant under Dr. Grant Woods, AJ has worked on properties in 13 different states, amassing over 25,000 acres of quality deer management. He now uses that knowledge to help clients find their dream hunting properties as a licensed real estate agent in Wisconsin.  


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