Feeding deer, while often well-intentioned, requires careful consideration. Not all human-provided sustenance is beneficial for them. Understanding deer’s specific dietary needs and the potential harms of inappropriate foods is important for their health and the ecological balance of their habitats.
Understanding a Deer’s Natural Diet
Deer are selective eaters, primarily consuming a diverse range of plant materials available in their natural environment. Their diet largely consists of “browse,” which includes the leaves, twigs, and buds of woody plants, along with “forbs,” which are broad-leaved herbaceous plants. They also consume “mast,” such as acorns, nuts, and various fruits, particularly during autumn when these high-energy sources are abundant. While they may eat some grasses, these are generally less preferred than browse and forbs.
A deer’s digestive system is uniquely adapted to process this natural vegetation. Deer are ruminants, possessing a four-chambered stomach, with the rumen being the largest compartment. This chamber hosts a complex community of microorganisms that break down cellulose, a primary component of plant cell walls, through fermentation. This specialized digestion allows deer to extract nutrients from fibrous plant matter.
Deer are “concentrate selectors,” meaning they prefer easily digestible, nutrient-dense plant parts. Unlike grazers, their smaller rumen capacity requires a specific diet. Their digestive microbes need two to three weeks to adapt to significant dietary changes. Sudden shifts to unfamiliar food sources can disrupt their digestive processes.
Foods to Avoid Feeding Deer
Deer possess a specialized digestive system, and certain human-provided foods can cause health issues or even be fatal. A primary concern is the sudden introduction of high-carbohydrate, low-fiber foods, such as large quantities of corn. Deer, as ruminants, rely on a delicate balance of microbes in their rumen to break down their natural diet of woody browse. When deer consume a large amount of corn, it can lead to a condition called acidosis.
Acidosis results from rapid carbohydrate fermentation, producing excess lactic acid that lowers rumen pH. This acidic environment kills beneficial microbes, impairing digestion and causing diarrhea, dehydration, and bloat. Severe cases can lead to nervous system issues or death. Prolonged acidosis may also cause laminitis, a painful hoof inflammation and lameness.
Hay, especially during winter months, can also be problematic. Deer’s digestive microbes adapt seasonally to process the available natural forage, which is often high-fiber woody browse in winter. If deer are not accustomed to hay, their rumen may lack the necessary microorganisms to digest it properly, leading to starvation despite a full stomach.
Many processed human foods are detrimental. Items like bread, potato chips, and sugary snacks lack nutritional value and cause digestive disturbances. Chocolate and candy are toxic. Domestic animal feeds, such as livestock feed or birdseed, are formulated for different digestive systems and can disrupt a deer’s gut microbiome. Moldy or spoiled food is fatal.
Toxic garden plants include:
Rhubarb
Elderberry leaves and stems
Castor beans
Parts of nightshade plants (potatoes, tomatoes, eggplant, peppers), especially when raw or unripe
Onions, garlic, leeks, and chives
Safe Supplemental Feeding Choices
If supplemental feeding is considered, choose options aligning with a deer’s natural diet. Commercial deer pellets are suitable, formulated to provide balanced nutrition, including essential proteins (14-20% or higher), vitamins, and minerals. These pellets support overall health, antler development, and reproduction.
Certain grains can be offered, but with careful consideration. Oats are generally well-tolerated by deer, being highly digestible and providing a good source of both protein and carbohydrates. They are often preferred over other cereal grains. However, all grains should be fresh and free of mold.
Legumes are beneficial due to their high protein content. Soybeans, highly digestible with up to 37% protein, are an excellent supplement. Deer are attracted to soybeans, especially if roasted, which also extends shelf life. Alfalfa and clover are valuable legumes, rich in protein, often used in deer food plots.
Fruits and vegetables can be offered in moderation as occasional treats. Safe options include apples, pears, persimmons, carrots, sweet potatoes, and squash. Provide these in small pieces to prevent choking. Wild nuts like acorns, beechnuts, hickory nuts, and pecans are also natural food sources. Always offer new foods slowly, in moderation, and ensure freshness to prevent digestive upset.
Guidelines for Responsible Deer Feeding
Responsible deer feeding prioritizes their health and natural behaviors. Always research appropriate food types, introduce new foods gradually, and avoid overfeeding. Understanding their unique digestive system is key to providing beneficial support without causing harm.