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Why Do Deer Grow Antlers?

While up North recently, I came across some Caribou with large antlers. I was told they were female, which surprised me as I thought only male deer had antlers.

Antlers are used to attract a mate and are used to defend the deer from predators. Antlers can help deer find food and keep them cool in warmer temperatures.

Read on if you want to learn more about why deer grow antlers, including why some female deer grow antlers.

Do female deer grow antlers?  Find out here

To Attract A Mate

The main reason deer grow antlers and one of the reasons that it is the male of the species that grow them is to attract a female deer for mating.

When the antlers grow during mating season, males display their antlers, with each male trying to become the dominant male.

Males will use their antlers for sparring as weapons to establish their dominance and compete for a mate.

Deer use their antlers to rub on trees. These marks show off their dominance over other males. Males with the largest antlers usually achieve the highest fertilization success. They are more likely to obtain mates due to their authority and competitiveness.

Defense

Deer have many ways of defending themselves. However, they will always try to avoid trouble using their keen sense of smell.

Antlers are helpful to protect the deer against predators and other deer, but the deer will only use them as a last resort. The defense is not the primary use for a deer’s antlers.

Deer will fight each other, and their antlers can lock themselves together, causing both deer to die of starvation.

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Finding Food

Deer do not eat meat and are herbivores eating fruits, nuts, and acorns when available.

The antlers can be used to knock down fruit from trees. Deer also use their antlers to knock down acorns and nuts when in season.

Relaxation

Antlers can get very hot in the summer, and they use their antlers in various ways to help them cool down and relax.

The deer can use the antlers to create depressions in the mud or dirt, allowing them to lie in or roll in to cool down, relax, and keep insects off.

How Does A Deer Grow Antlers?

The antlers grow from two base points on the deer’s head. These two points are called pedicles, and the antlers are bone tissue structures.

The velvet, which is a soft tissue, covers the antlers and feeds nutrients to the growing structure while growing. The velvet contains arteries and veins used to provide the nutrients.  

Testosterone is needed to grow the antlers, which is why the male deer is generally the only one in the species with the antlers.

Testosterone in male humans plays a massive role in developing reproductive tissues and promotes characteristics such as bone and muscle mass.

The testosterone in the male deer is very similar and plays a vital role in the deer finding a mate.

Deer survive the harsh weather conditions in some clever ways.  Find out more in this article I wrote

Why Do Some Female Deer Grow Antlers?

Although the male buck produces testosterone, essential for antler growth, some female deers create this. 

An antlered doe, although rarely occurs because of an imbalance in the hormones that cause higher levels of testosterone to be present.

Flinn said an antlered doe occurs because of a hormone imbalance that causes higher male testosterone levels, causing antlers to grow.

Some antlered does turn out to be hermaphrodites having both male and female sex organs, although these are rare, with estimates between 1 – 1000 to 1 – 5000 being cited.

There are also deer, which have rare genetic defects that cause a set of antlers to grow. These antlers do not grow from pedicels but from the skull plate inside.

These defects are permanent antlers and do not shed like other deers. It has been estimated that one female in every 20,000 has small antlers by the Maryland Department of Natural Resources.

Which Species of Deer Grow Antlers?

The deer native to North America all have antlers. These two deer native to North America are the whitetail deer and mule deer, and a subspecies of the mule deer, the Pacific coastal blacktail, also grows antlers.

The elk, caribou, and moose all have antlers, with the moose having the largest antlers and being the tallest mammal in North America, standing six feet tall. Antlers are grown from the age of one year old.

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Are Antlers the same as Horns?

Whereas other North American mammals such as Bison, antelopes, goat, sheep, and cattle have horns, these are not the same as the antlers that deers grow.

Horns are composed of the same material as fingernails and hair, keratin on the outside and inside, they are bone. Whereas horns grow from the base upwards, antlers grow from the tip.

Another difference between horns and antlers is that antlers are shed annually, whereas horns are not. Antlers are deciduous and are shed annually and grown each year anew.

The hairy, covered small bumps on a baby fawn’s head are pedicels, not antlers. 

Do Deer Shed Their Antlers Annually?

High levels of testosterone during the summer slow the growth of the antler. The velvet is constricted by the veins and arteries and cuts off the blood supply to the antlers.

In early September, the velvet dries up almost entirely and sheds, leaving the bony structure for the upcoming mating season in Autumn.

Once the mating season has finished, the deer shed their antlers between December and March.

The process does not hurt the animal and can take 2 to 3 weeks. The tissue slowly disintegrates between the pedicles and the antler, causing them to come away gradually and eventually fall off.

The deer will not have to wait long as new antlers grow in the spring to prepare for a new mating season.

The length of time a deer keeps his antlers before they shed depends on his general nutrition and genetics.

Do Antlers Indicate Health Concerns?

The number of points on a deer’s antler is called the tine, and the amount can depend upon his health, genetics, how well he has fed during the winter, and age.

Thus, antlers do not always grow the same each year with different sizes caused by the health of the deer and its food supply.

Because of damage from general wear and fighting over time, it is common to see deer with antler points that have been blunted or broken off entirely.

If you want to know why mammals have tails (and we don’t) then click here.