Most deer in North America die from one of five causes: predation, hunting, disease, vehicle collisions, or winter starvation. The balance between these varies dramatically depending on whether the deer is a fawn or an adult, and whether it lives in a rural wilderness area or near suburban sprawl. A white-tailed deer that survives its first few months of life can expect to live about 6 years if male, or closer to 8 years if female, but relatively few die of old age.
Predation Hits Fawns Hardest
For deer under a few months old, predators are the overwhelming cause of death. A study tracking 71 white-tailed deer fawns in the Southern Appalachian Mountains found that 82% of all known mortalities were from predation. Coyotes were responsible for 40% of fawn deaths, black bears for about 22%, and bobcats for nearly 13%. Cumulative fawn survival to 12 weeks of age was just 15.7%, meaning roughly five out of every six fawns died before reaching three months old.
Coyotes are particularly effective fawn predators because they hunt consistently over a long stretch of the summer, while bears and bobcats tend to be more opportunistic. On coastal islands and in fragmented habitats where coyote populations are established, coyote predation alone can account for nearly half of all fawn deaths from any cause.
Adult deer face far less predation pressure in most of the eastern United States, where wolves have been absent for over a century. In states with wolf or mountain lion populations, predation remains a significant factor for adults as well.
Hunting Is the Leading Cause for Adults
Across much of the country, legal hunting is the single largest source of mortality for adult deer. Virginia alone reported 227,302 deer harvested during the 2025–2026 season, and that state represents just a fraction of the national total. State wildlife agencies deliberately set harvest quotas to manage populations: in Virginia, 58% of counties currently have deer numbers above target objectives, which is why liberal bag limits remain in place.
Hunting mortality is heavily skewed toward bucks. Antler restrictions and hunter preference mean that adult males face substantially higher odds of being killed in any given year than does. This is one reason males average shorter lifespans (about 6 years) compared to females (about 8). The oldest known white-tailed deer on record was a doe in Georgia that reached 22 years.
Vehicle Collisions Kill Over a Million Annually
Between 1.5 and 2.1 million deer-vehicle collisions occur in the United States every year. These crashes also kill 200 to 440 people and cause more than $10 billion in property damage annually. For deer living near roads and suburban edges, cars are one of the most common killers, especially during the fall rut when bucks are chasing does across roadways with little regard for traffic.
Vehicle collisions tend to be a bigger factor in fragmented landscapes where roads cut through deer habitat. In more remote areas with lower traffic volumes, this cause of death drops significantly.
Disease Can Devastate Local Populations
Two diseases stand out as major deer killers: chronic wasting disease (CWD) and epizootic hemorrhagic disease (EHD). They work very differently, but both can cause dramatic local die-offs.
Chronic Wasting Disease
CWD is a slow, always-fatal neurological disease caused by misfolded proteins called prions. It spreads through direct contact and contaminated soil, and there is no cure or vaccine. Research suggests that when CWD prevalence in an area exceeds 25 to 30%, the deer population cannot sustain itself. A study in Arkansas documented an average 17% annual decline in deer density across three study sites with high CWD prevalence, with males declining about 23% per year and females about 15%. In Colorado, mule deer numbers dropped an estimated 45% over 20 years in an area where roughly one in four deer was infected, even though habitat was suitable and hunting pressure was minimal.
CWD is especially concerning because it doesn’t burn through a population quickly and disappear. It persists in the environment for years, continuing to infect new animals long after initial outbreaks.
Epizootic Hemorrhagic Disease
EHD is a viral disease spread by tiny biting midges, not from deer to deer. It strikes in late summer and early fall and can kill an infected deer within days. Outbreaks tend to be worst when a wet spring (which breeds large midge populations) is followed by a hot, dry summer that concentrates deer around shrinking water sources. The first hard frost kills the midges and stops transmission entirely.
EHD outbreaks can be intense but localized. A single outbreak might kill dozens of deer around one creek bottom while leaving deer a few miles away untouched. Unlike CWD, EHD has not been shown to cause lasting population-level declines, though local herds may take a few years to recover.
Winter Starvation and the Fat Reserve Clock
Cold weather kills deer through a slow process of energy depletion rather than from the cold itself. Adult deer routinely lose up to 20% of their body weight over winter, and this happens regardless of how much food is available. During winter months, deer derive as much as 40% of their daily energy from stored fat tissue. If those fat reserves run out before spring green-up arrives, the deer dies.
This is why biologists discourage feeding deer in winter. A deer’s digestive system adjusts to a winter diet of woody browse over several weeks, and suddenly introducing corn or other rich foods can cause fatal digestive problems. The real determinant of winter survival is how much fat the deer stored during the previous fall, which depends on summer and autumn food quality, not what’s available in January.
Winter kill is most significant in northern states and Canadian provinces with prolonged snow cover. Deep snow makes it physically exhausting for deer to move, burning calories faster while also burying the browse they depend on. In severe winters, fawns and older deer are the first to succumb.
Fences and Other Infrastructure
A less obvious but real source of deer mortality is fencing along roads, farms, and rangeland. A study in Colorado and Utah found an average of 0.25 ungulate deaths per kilometer of wire fence per year. Animals typically die by getting caught between the top two wires while attempting to jump. Juveniles are eight times more likely to die in fences than adults, and woven-wire fences topped with a single strand of barbed wire are the most lethal design.
While fence deaths don’t rival predation or hunting in overall numbers, they add up across the millions of miles of fencing that crisscross North American landscapes. For individual properties, switching to wildlife-friendly fence designs with a smooth top wire and adequate spacing can significantly reduce these deaths.