Deer are fascinating hoofed animals known for their antlers, which they grow and shed each year.

Key idea: The word "deer" has evolved to specifically refer to animals in the Cervidae family, and different terms are used for male, female, and young deer depending on the species.

The word "deer" used to mean any wild animal. For example, in Old English, "dēor" meant any wild creature. Over time, around the year 1500, the meaning became more specific to the animals we call deer today.

In many modern languages, words similar to "deer" still mean "animal." For instance, in German, "Tier" means animal.

For many types of deer, a male is called a buck and a female is a doe. But these names can change depending on the type and size of the deer. For example, a male red deer is called a stag, and for very large deer, males are bulls and females are cows, just like cattle.

Young deer are often called fawns, or calves for larger species. A group of deer is called a herd. The word "cervine" is an adjective used to describe things related to deer, coming from the Latin word for stag or deer.

Key idea: Deer are highly adaptable and live in diverse habitats across most continents, with Asia having the greatest variety of species.

Deer live in many different types of environments, from very cold tundra to hot, wet rainforests. While you might often think of deer living in forests, many prefer areas where forests meet open spaces like prairies. This gives them both cover and places to find food.

Most large deer species live in forests that lose their leaves in autumn, mountain forests with cone bearing trees, tropical dry forests, and savannas around the world. Sometimes, clearing small open areas within forests can actually help deer populations by letting their favorite plants grow.

Deer are found almost everywhere except Antarctica and Australia. However, Australia now has six types of deer that were brought there by people and have made homes in the wild. Africa has only one native deer, the Barbary stag, found in the Atlas Mountains.

The highest number of different deer species in the world is found in Asia. Europe has fewer types of deer, but you can find red deer, roe deer, and fallow deer in many national parks there. In North America, the Canadian Rocky Mountains and Columbia Mountains are home to five different deer species, including white tailed deer, mule deer, and moose.

Key idea: Deer are distinguished by their temporary antlers and vary greatly in size, from the tiny pudu to the massive moose.

Deer are the second most diverse family of hoofed animals with an even number of toes, after cattle and their relatives. Deer are different from antelopes because their antlers are temporary and grow back every year, unlike the permanent horns of cattle.

Typical features of deer include long, strong legs, a small tail, and long ears. Deer come in many different sizes. The largest living deer is the moose, which can be almost 2.6 meters (8 feet 6 inches) tall and weigh up to 800 kilograms (1,800 pounds). The smallest deer is the northern pudu, which is only about 32 to 35 centimeters (12.5 to 14 inches) tall at the shoulder and weighs just 3.3 to 6 kilograms (7 to 13 pounds).

Males are usually larger than females in most species, and only males have antlers, except for reindeer where females also have them. Deer coats are usually red or brown, but can range from dark chocolate brown to grayish. Some species, like the chital, have white spots. Deer shed their coats twice a year, changing from a thin summer coat to a dense winter coat.

Key idea: Antlers are bony growths on most male deer that are shed and regrown annually, primarily used for mating displays and combat.

All male deer have antlers, except for the water deer, which has long, tusk like canine teeth instead. Female deer generally do not have antlers, though female reindeer are an exception, growing smaller antlers than males.

Antlers start growing from a bony base on the skull when a deer is about a year old. The first year, it might be a simple spike. Each year after, the deer sheds its old antlers and grows new ones that are usually larger and have more branches. This process continues throughout their life.

Antlers first grow as soft tissues covered in "velvet," which is skin and fur. This velvet supplies blood and nutrients. As the antlers grow, they harden into solid bone. The velvet then dries up and peels off, leaving the hard antlers.

Antlers are mainly for attracting mates and for fighting other males. The branches, or tines, on antlers help deer lock together during fights, which protects their faces from injury. Larger antlers usually mean a male has a higher social status and is more aggressive. They can also show that a male is healthy and has good genes.

Key idea: Deer have specialized teeth and a diet focused on nutrient rich plants, often lacking upper front teeth and sometimes having tusk like canines.

Most deer have 32 teeth. Like other animals that chew cud, they do not have upper front teeth. Instead, they have a tough pad on their upper jaw that helps them pull off plants. Their cheek teeth have crescent shaped ridges that are good for grinding various plants.

Some deer, like the Chinese water deer and muntjac, have long upper canine teeth that look like sharp tusks. Other deer species might not have upper canines at all.

Deer are primarily browsers, meaning they mostly eat leaves, twigs, and young shoots from plants, shrubs, and trees. In colder areas, they might eat lichens in winter. They have small stomachs compared to other cud chewing animals and need food that is rich in nutrients.

Instead of eating large amounts of low quality, fibrous food like cows do, deer carefully select easy to digest items such as fresh grasses, soft twigs, fruits, and fungi. They need a lot of minerals, like calcium and phosphate, to help their antlers grow strong.

Key idea: Deer mothers typically raise their fawns alone, and fawns are born spotted for camouflage, staying hidden for their first week of life.

Most deer species are "uniparental," meaning only the mother cares for the young, which are called fawns. A mother deer, or doe, usually has one or two fawns at a time. The mating season typically starts in late August and can last until December.

The time a fawn spends developing inside its mother, called the gestation period, can be up to ten months for some species. Most fawns are born with white spots on their fur, which helps them blend in with their surroundings. These spots usually disappear by the end of their first winter.

Fawns can take their first steps within minutes of being born. The mother licks her fawn clean to remove any scent that might attract predators. She often leaves the fawn hidden while she goes to graze, sometimes gently pushing it down with her foot to keep it still. Fawns stay hidden for about a week until they are strong enough to walk with their mothers. They stay with their mother for about a year. Male fawns usually leave and do not see their mother again, but female fawns might return with their own young to form small groups.

Deer can carry diseases that affect other animals and sometimes humans. For example, in some areas, deer can be involved in spreading bovine tuberculosis, a disease that affects cattle. In North America, deer, elk, and moose can get chronic wasting disease, a serious illness that affects their brains.

Key idea: Deer have a rich history of interaction with humans, serving as food, cultural symbols, and economic resources, while also posing challenges like vehicle collisions and ecological impacts.

Deer have been important to humans for a very long time. In ancient times, early humans hunted deer for food. For example, Homo erectus in China ate sika deer, and red deer were hunted in Germany. Cave paintings from the Stone Age, like those in Lascaux, France, show many images of deer.

Deer have also played a big role in human culture, art, and stories across many civilizations. They appear in the art of the ancient Egyptians, Celts, and Greeks. In Japanese Shintoism, sika deer are seen as messengers from the gods. In China, deer are linked to good health and long life.

In medieval Europe, deer were often shown in hunting scenes and on family crests. The name Oscar, for example, comes from an Irish word meaning "deer friend." Deer are also central to many fables and literary works, from ancient Sumerian writings to modern stories like "Bambi" and "The Yearling."

Deer are important economically. Their meat, called venison, is nutritious and can be obtained through hunting or farming. Deer hunting is a popular activity in the U.S., generating a lot of money from license sales that help fund conservation efforts. Deer farming, especially for red deer, is also a significant industry in countries like New Zealand and Ireland.

However, deer can also cause problems. About 1.5 million car accidents involving deer happen each year in the U.S., leading to human deaths and significant property damage. In places like New Zealand, where they have no natural predators, deer populations can grow too large and become pests, harming native plants and competing with livestock.