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What Do Deer Eat? Investigating the Diet of the Whitetail

What Do Deer Eat
Getty Images: Dean Fikar

Let's take a closer look at what it is exactly that whitetail deer eat and why. 

Before all of you hardened fellow, lifelong whitetail deer hunters contemplate this question and chuckle let's take a little quiz: What are the names of all the crankbaits that you have in your tackle box? Having said that, yes, we should all know by now what the deer we know and love like to eat to survive, but without having it all right in front of us, we might just need a little kick in the pants to help us remember.

This is not to mention all of the new and younger prospective hunters out there who just want to see a list of these items, not to mention the science behind why deer eat what they eat.

Whitetail deer hunting is what we live for. Knowing that, we have spent our lives and our hard earned dollars in the effort to know this quarry like the back of our hand, and we don't spare the horses to do it.

In the fall we hunt them, and in the spring we love them; the way they are born in the new warmth of the early year, and the way that grow right before our eyes, especially on our trail cameras. We grow food plots to give them an added edge in their growth and we tend that field like it was a cash crop. So, let's look at what the science is behind the whitetail diet, what they eat in nature, and what it is that we've found to use as high energy supplemental feed for them. 

The Science Behind What Whitetail Deer Eat

“A deer eating apples in my apple orchard in Maryland near the ocean,” writes Janice E. Nanna in sharing her shot

Posted by The Naturalist's Notebook on Saturday, October 28, 2017

First of all, there are good whitetail deer populations from Texas to New York, and from Alabama to Minnesota. The plants and mast they eat from these states are both similar and completely different since the regions are so far apart. Deer love soft mast such as berries in the summer and hard mast such as acorns in the fall, based on their availability. This makes their diet much the same as most creatures in the wild: seasonal.

The best way to put it is probably as the Mississippi State University Deer Ecology & Management Lab study that said:

"Understanding diet selection by white-tailed deer is best accomplished by first knowing what whitetails "should" eat."

Since the whitetail deer have a more narrow snout and long tongue that allows them to delicately seek out specific plant parts, they tend to have a more competitive advantage over other like minded ruminants when it comes to foraging.

Since their "relatively smaller and less complex gastro-intestinal tract requires they eat forages that are of relatively higher quality and more easily digestible than forages eaten by cattle, elk and moose," you may think that their diet would have to eliminate certain foods like acorns, which come loaded with tannins that are difficult to digest, but the fact is that they have a very active salivary function whose glands produce a highly active enzyme that breaks down and deactivates secondary plant compounds such as these to allow deer to eat them in quantity.

Still, they need to eat forages that are of a higher quality and more easily digestible than the same that are eaten by rumen like cattle, elk and even the closely related moose.

Not only that, but deer have been documented as having starved to death with their stomachs full of low quality forage in areas where food sources were depleted and the deer ate what ever was available. Not everything can be an ideal deer food with high protein content. Now if you're still waiting for the list of what the deer are eating, you may be in for a surprise since the study indicates that in the southeast alone, whitetail deer have been documented to eat over 400 species of plants and other forage, and there's really no use in listing them all right now.

As we know here in the northeast, deer are a product of their environment and generally adapt to what they have available such as all of the products of farming. Here is one of the greatest reasons why farmers across the nation are granted yearly nuisance permit to cull from the deer herd over the course of the entire year.

This may put a burr under the saddle of some hunters, but the fact remains that crop damage by whitetail deer is very real and very detrimental to our highly valued farming communities. Farmers have told me in the past that they "walk right down the edge of a 200 yard squash field and take one bite out of every single one; now I can't sell it"

As farmers and whitetail deer are quite adaptable, many crop growers now use some fields strictly for the seeds produced while using what they can from the fruit. Since most squash fields are completely harvested by the time deer season rolls around, it then behooves the deer hunter that wants to hunt near a food source to find something else that continues its presence even when other items are gone such as corn, soybeans, or acorn mast producing areas.

For the many things that deer are documented to eat, it still comes down to the fact that only about a third of those food items or less make up over 90 percent of their overall diet.

"Throughout the range of white-tailed deer, greater than 85 % of their overall diet consists of browse, forbs, and mast."

Browse includes the leafy parts of woody plants, forbs, which are herbaceous broad-leaved plants, including some agricultural crops, hard and soft mast (including seeds), grass and even mushrooms or lichens as they can find them. Most of us have probably seen deer browsing in a park or right in our own yards for grass, just to supplement their diet, but it is considered a low quality forage for an animal whose faster digestive process requires a more readily digestible food source.

More important are the wide variety of agricultural crops eaten whenever available since they tend to be more nutritious and better as digestible foods. In northern climates, leaf buds and the winter foliage of many evergreen trees and shrubs, like arborvitae and yews are impactful food sources as well.

Ok, So What Do Deer Eat?

The acorns are starting to fall and the squirrels and deer are busy eating them! How many different oaks can you identify?

Posted by Fat Bird Farms on Monday, August 31, 2020

Although these are only some of the main foods that deer like to eat, the quantity of these different foods differ throughout the year and the region you are hunting. The one main reason why deer can eat corn is they can only glean small amounts of it from leftover crop fields as a supplement to their diet of normal browse.

The real reason why most state wildlife departments frown on the use of corn to feed deer is because that sharp changes in their diet, switching from browse to fermentable carbohydrates such as corn, can cause acidosis in deer and kill them. It is said that deer can even starve with a stomach full of alfalfa they cannot digest simply because their bodies cannot adapt quickly enough to it as a food source.

In other words, they can have corn and alfalfa as a part of their diet, but not all at once and in quantity.

During the growing year, deer enjoy a wide variety of fruits and vegetables (ask any farmer) that they can reach such as apples, grapes, plums, cherries, pears, pumpkin, carrots, snap peas, red peppers, squash, even honey locust, and many more. Basically they'll try anything and we'll try anything if we think that it will attract them.

As stated, listing the extreme variety of things whitetail deer are documented to eat would be exhausting. So, we'll try to stick to some of the better known items on a deer's grocery list. Obviously, in areas where these fruits and vegetables are grown and where deer exist, you're going to have some conflict, whether it be from the deer actually eating, ruining, or destroying the crop to poachers using an uncommon food source to try and attract deer illegally.

Probably the most important source of nutrition for deer is still the many browse plants which can be shrubs or young trees within reach of deer. Browse plants are almost always available in one form or another, no matter what time of year it is since there is usually some part of the bud or twig that can be used as nutrition.

Some of the most important mast items are the nuts like chestnuts and especially the inimitable acorn which many feel is the whitetail deer's favorite. Beech nuts, hickory nuts, and even walnuts may be a part of a whitetail's diet, but even though they are much more difficult to open, let's not count them out just yet.

And what about the cereal grains? Oats, wheat and rye are on the menu, but it is also a case of opportunistic feeding. Nuts and mushrooms are high in phosphorous which help deer, especially bucks, to replace what is needed for antler mineralization.

Maybe the truer question should be, what is it that deer don't eat?

Food Plots

Good food plots keep the deer close!

Posted by Oak Creek Whitetail Ranch on Wednesday, January 13, 2021

For folks that are wiling to do the work and want to supplement their resident whitetail population's food sources, the food plot is just what the doctor ordered.

The usual choices are perennials like alfalfa and clover, along with cereal grains like wheat, rye, oats, and triticale, and maybe the most popular come in the form of brassicas: the genus of a group of broadleaf perennials that belong to the mustard family including cabbage, cauliflower, broccoli, collards, rutabaga, mustard, kale, swede, radish, turnip, rape, and canola.

Brassicas are an excellent choice in northern climates where they can survive the snow and cold and continue to come back strong.

Whether it's winter feeding that you're hoping to create to keep the deer in your area, or supplemental feeding, the preferred foods of the whitetail deer still come in the form of the food plants that these herbivores know the best.

Certainly there is a difference between deer management and deer baiting, but there are still some who hold that food plots offer an unnatural attraction for deer.

Final Thoughts

Whether the deer find a new food or use the natural resources around them they still have the same nutritional needs as they did throughout their history. They still use up much of their fat reserves during the rut, and have the need to survive the winter months by finding what they can based on the region where they live.

This can be a cold weather area or a more southerly part of North America, but it usually comes down to woody browse that they rely on the most. Since we have an endless amount of studies as to what deer feeding is all based on, then we should have all of the answers as to what a deer's diet really is, right?

Well, just forget about that whitetail wizards, because until the deer start talking and tell us everything that we want to know about them, we're going to continue to watch and learn everything that we can about our favorite game animal.

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NEXT: 9 DEER FOOD PLOT TIPS TO APPLY TO YOUR HUNTING GROUNDS

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What Do Deer Eat? Investigating the Diet of the Whitetail