This small herd of deer may be fun to watch out your window and to feed when they don't look so good, but how beneficial is feeding them really?

The deer look so sad and thin! Can’t I feed them, pretty please?

Deer have the ability to eat a forest to the brink of desctruction, so then why would humans providing them supplemental food be a bad thing? (phot cred: Doris Rafaeli)
The deer population in this region of the country can eat the entire  understory of a forest, so why would it be a bad thing to supplement their diet and feed them as well?

Did you know that deer were once referred to as “a great credit to nature?” Many people don’t think of White Tail Deer in the same manner, but John Muir once wrote, “Standing, lying down, walking, feeding, running even for its life, it [deer] is always invincibly graceful, and adds beauty and animation to every landscape — a charming animal and a great credit to nature.”


Feeding this credit to nature may be second nature to some of us when the winter rolls around and the deer are looking highly stressed (they may lose anywhere from 20-30% of their body weight!) by the cold weather and snow, but is it really helping them as much as us animal lovers hope it is?

Unfortunately, in most cases it’s not. In fact, sometimes feeding the deer can be so devastating that it ends up killing them! Also, in many states, Pennsylvania included, feeding the deer is highly discouraged due to issues with overpopulation and disease spreading.

Let’s take a look at why feeding the deer isn’t the greatest thing. First off, the typical “Deer Food” is a corn based mixture; however deer are unaccustomed to eating corn as they switch from green, leafy plants to woody browse such as bark, lichen, and even dead leaves in the winter. This dietary switch happens gradually throughout the changing seasons and has become something that the deer are accustomed to. Just like a human, when the microorganisms in the stomach come across something very strange and foreign, it takes longer for them to digest the food. When the deer are suddenly introduced to corn, apples, and other “deer food” we like to give them in the winter, the microorganisms don’t know what to do with the foreign objects and the deer will end up with a satisfied full feeling even though the food isn’t being properly digested. This is called Enterotoxemia, or the “Overeating Disease.” Essentially, the deer will start to feel like we do when we get food poisoning and if the deer continue to eat the corn or the food that we provide thinking it gets full off of it, the deer could potentially starve to death as the nutrients are never actually being absorbed!

Secondly, there are so many deer in this area that overpopulation has had a detrimental effect on forests and neighborhoods alike. Due to overhunting, the numbers of natural deer predators (like coyote, bobcat, and wolves) have decreased so dramatically that the deer populations exponentially increased. This causes problems to the forests as the deer will continue to eat any new forest growth which can impact what other native species are able to live in the forest. Many species of native wildlife require small trees, thickets, and a healthy forest understory in order to live but when a population of deer eats all of that, the biodiversity of that forest isn’t maintained. Deer also will avoid invasive plant species, allowing for that plant species to out-compete the native ones.  When the deer population is balanced, so is the forest. The forest and the deer rely heavily on each other for survival and continued growth.

Not only do they cause problems in the forest, but they also will wreak havoc in residential areas. These areas that report a higher population of deer also have more road kill reports. This causes damage to cars and to human health as well. Hunters have helped to manage these populations, but without natural predators, the deer run rampant through neighborhoods and along roads.

When deer are grouped together in one area for supplemental feeding, this is a perfect opportunity for diseases like Chronic Wasting Disease (CWD), Tuberculosis, and Mange to spread. CWD affects the brain and may cause the deer to behave unnaturally. They may be found walking in repeated patterns and these patterns may take them out towards roads where they become a human safety concern.

Of course, we understand the urge to take care of an animal that looks in need, but the best thing that you can do for the deer populations is to not feed them! This will help manage the population as a whole and to prevent unnecessary individual deaths.

Check out these links for some more explanation behind the science of Enterotoxemia, CWD, and Forest health!

Enterotoxemia Intro and Enterotoxemia Pathology

Disease Spread in Concentrated Deer Populations and CWD in Cervid Brains

Ruminant Stomach Biology

Please Don’t Feed the Deer! and Deer Management Practices

The Relationship Between Forests and Deer


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