Have you ever gone into the woods with your thermal monocular hanging down your neck and your hunting equipment in your hands and after a few hours, you exit the woods but with a question in your mind – how old was the deer you were just looking at? Probably not, but regardless, you are here, so we’ll explain the factors that go into the average lifespan, and answer that question for white-tail, mule deer, male deer, and female deer.
How Long Do White-Tail Deer Live?
The average wild white-tail deer lives about 4.5 years. The oldest wild deer are reported to live into the late teens, with the oldest wild white-tail deer on record being 19. The oldest wild mule deer on record was 20, and the oldest wild black-tailed deer on record is 22. You can read more on this here.
Wild deer have shorter lifespans than captive deer. We go into what plays a role in a deer’s lifespan below, as well as break down the differences by sex and species.
How Long Do Mule Deer Live?
The average wild mule deer lives between 9 and 11 years according to The National Wildlife Federation.
How Long Do Male Deer Live?
Male deer tend to have shorter lifespans than female deer due to the need to consume more calories, behavior differences, hunting, and other reasons. They live on average about 2 years less than the average doe.
How Long Do Female Deer Live?
Female deer live on average about 2 years longer than male deer. When looking at various resources, this puts the average lifespan at about 6 years. (https://www.deerassociation.com/whats-oldest-deer-record/, https://tpwd.texas.gov/huntwild/wild/game_management/deer/age/, https://www.nwf.org/Educational-Resources/Wildlife-Guide/Mammals/Mule-Deer)
Buck To Doe Ratio & How It Relates To Population
You’ll often hear about buck to doe ratios. This relates to how many bucks there are compared to doe. For example, a 1:5 buck to doe ratio means there is 1 buck for every 5 doe in that specific area. You’ll hear about this number when regions are thinking about controlling population, and overall age of the deer population of that area. There is a whole lot to go into depth on this subject. You can read more about the Buck To Doe Ratio here: https://tpwd.texas.gov/huntwild/wild/game_management/deer/age/
There are a lot of factors that determine what the age of a deer is or for how long they can survive. So, if you want to know how old that deer is, read on:
Factors That Affect Deer Mortality & Lifespan
Many factors contribute to and determine the lifespan of a deer. Some of these factors include:
Deers that live in captivity generally do live longer than their peers in the wild. This is because those that live in captivity are often cared for and are safe from prey. Whereas those that live in the wild are open to a lot of dangers. Also, starvation is another factor that affects the deer that live in the wild. During heavy snowfalls, the waters can be sealed up, and/or erosion might occur and when there is drought, they may be left without food for days. This is just a couple of examples, but a deer lives a much more dangerous and difficult life in the wild, shortening the average lifespan.
Hunting is one of the major factors that contribute to the drastic difference between the lifespan of deer that live in the wild and those that live in captivity. A publication by the Quality Deer Management Association Whitetail Report reported that hunting alone results in the death of 5.5 million deer annually. Deer do not live long in regions that have high hunting density. The live longer lives in regions where the hunting density is low.
Extreme Weather & Climate:
Unlike humans that live in homes, deer that live in the wild are open to living outside even when the conditions are harsh. Deer do not live long in regions where there is a severe weather conditions on a frequent basis. For example, the deer in Michigan’s upper peninsula where there are brutal snowfalls and hot winter temperatures, do not live as long as those in south Texas, where the weather conditions are temperate all year round.
Proximity To Roads
Annually, there are about a million cases of deer involved in auto accidents. Most of these deer end up dying while those that are lucky enough to survive the accident are left injured, which makes them an easy target for predators, or can hinder their ability to find food.
Another unforeseen threat to the lives of deer is a forest fire. These can be common in the western U.S. states and severely hurt dear populations where these fires occur.
Deers that live in the wild often fall prey to predators.
Due to their wide range of distribution, Coyotes are known to be the cause of a large portion of predation issues in areas throughout the white-tail deer range. A study carried out by the U.S. Forest Service Southern Research Station located at the Savannah River Site in South Carolina reported a total fawn mortality of about 70 percent at the site, and approximately 80 percent of these mortalities were reported to have been done by coyotes. Mountain lions, black bears, and bobcats are some other well-known deer predators. The most common predator for deer depends on the location you are considering.
Apart from hunting and predation, auto accidents involving deers account for about a million death or injury to deers per year. Those that survive the accidents are often left limping till their death
Deers, just like humans and every other animals, can be affected by the outbreak of a disease.
The diseases most common to deers are: chronic wasting disease (CWD), epizootic hemorrhagic disease (EHD), and bovine tuberculosis (BTB).
The chronic wasting disease is a disease that affects the neurological system. It is transmitted through saliva or other body fluids from deer. It is difficult to control and there is no known treatment for the disease.
Biting flies transmit epizootic hemorrhagic disease, thereby causing extensive hemorrhaging. Its mortality rate is high and no treatment is known for the disease. The outbreak of EHD varies annually, ranging from something as low as infecting a few percentage of the deer’s population to something as severe as killing up to 50 percent or more of their population.
BTB is a chronic and fatal disease that affects the respiratory system. It is transmitted through the exchange of respiratory fluid, typically from sneezing or coughing. Also, there is no known treatment for the disease.
A little more about mortality:
Leonard Lee Rue III recorded in his book – “The Deer of North America,” that deers could live for about two decades. He did mention of a Vermont doe that lived for 19 years.
A Research result reported by the Quality Deer Management Association stated that whitetail deer living in captivity can live for up to 18 years, while quite a few have been reported to make it past two decades with some living for up to 23 years of age.
However, this is not the case for deers that are living in the wild. Deer that live in the wild are reported to have an average lifespan of four and a half years.
Also, just like it is in humans and most other living species, male deer typically have a lower lifespan when compared with female deers. Only a few male deer that lived in captivity had been reported to live for more than 15 years. Male deer in the wild live an average of about 3 years while female deer in the wild could live for up to 6.5 years. This is why deer hunters consider it a trophy when they capture a deer that is older than 3 years in age.
Max DesMarais is the founder of Hiking & Fishing. He has a passion for the outdoors and making outdoor education and adventure more accessible. Max is a published author for various outdoor and marketing websites. He is an experienced hiker, backpacker, fly fisherman, trail runner, and spends his free time in the outdoors. These adventures allow him to test gear, learn new skills, and experience new places so that he can educate others. You can read more about him here: hikingandfishing/about