How Long Do Deer Live? Lifespan of Common Deer Species

Deer lifespans compared

How long a deer lives depends on its species, its sex and above all on where it lives: how much it is hunted, how many predators and roads are nearby and how hard the winters are.

These figures are averages and ranges from field studies, and they vary from one population to another. A white-tailed deer in a heavily hunted area may have a much shorter expected life than one in a protected park.

White-tailed deer: short average, long potential

The gap between the average and the maximum is huge in white-tailed deer. Many fawns die in their first summer, mainly to coyotes, bears and bobcats, and in heavily hunted areas many bucks are taken by their second or third autumn. Does tend to live longer than bucks, and in lightly hunted populations it is not unusual to find does 8–10 years old or more.

In captivity, safe from predators, traffic and hunger, white-tails can live into their late teens and have reached about 23 years.

Red deer and roe deer

Red deer are bigger and grow more slowly. On the Isle of Rum in Scotland, where red deer have been studied for decades, many hinds live into their teens, and the oldest pass 20 years. Stags usually die younger, because the effort of the autumn rut and fighting wears them down.

Roe deer are small and breed fast, so their lives are shorter. Many live up to about 10 years, and the oldest wild animals reach about 15–17 years. Young roe deer are vulnerable to foxes, lynx and wolves, to farm machinery mowing hay fields in early summer and to cold, wet weather soon after birth.

Why do bigger deer live longer?

Across mammals, larger species tend to grow more slowly, breed later and live longer, and deer follow this pattern. A roe doe can breed in her second year and often raises twins every year, while a red deer hind usually has her first calf at about three years old and then a single calf most years. Small, fast-breeding species can afford to lose many individuals young, because the population refills quickly. Larger, slower-breeding species rely on adults surviving many seasons.

What kills deer?

Deer face different dangers at different ages:

• Predators. Wolves, cougars, lynx and jaguars can kill adults, while coyotes, foxes, bears, bobcats and eagles mainly take fawns.
• Hunting. In much of North America and Europe, regulated hunting is the main cause of death for adult deer, and wildlife agencies use it to keep numbers in balance with habitat.
• Vehicles. Collisions with cars kill very large numbers of deer each year on both continents, especially in autumn.
• Winter and starvation. Deep snow and poor food can kill fawns and old deer in the north, and bucks that lost condition during the rut.
• Disease and parasites. Chronic wasting disease, a fatal prion disease, is spreading among North American deer, and outbreaks of hemorrhagic disease spread by biting midges can kill many deer in late summer.

Old age itself is rarely the end. As a deer’s teeth wear down in its teens it can no longer chew tough food well, loses condition and becomes easy prey or dies in winter.

How biologists tell a deer’s age

There is no reliable way to age a deer from its antlers, because antler size depends heavily on food and genetics. Instead, wildlife biologists look at the teeth.

Tooth replacement. A fawn’s lower jaw has three baby premolars. In white-tailed deer these are replaced by permanent teeth at about 18 months, so a deer with baby premolars in autumn is a fawn or yearling. This method, developed for white-tails by C. W. Severinghaus in 1949, is still widely used.

Tooth wear. In older deer, the sharp ridges on the cheek teeth wear down year by year, exposing more of the dark inner layer called dentine. Experienced biologists can estimate age classes from the pattern, although the method becomes less precise after about 4 years.

Cementum annuli. The most accurate method is to slice a tooth root and count its growth layers under a microscope, a little like counting tree rings. Each year adds one light and one dark band.

Myths about deer age

Myth: Deer grow one antler point per year. A yearling white-tail on rich food can carry eight points, while an old buck in poor habitat may have fewer. Point counts say much more about nutrition than age.

Myth: Gray faces mean very old deer. Older deer often have longer snouts and grayer faces, but coat color also varies with season and individual, so it is only a rough guide.