While up North recently, I came across some caribou that had large antlers. I was told they were female, which surprised me as I thought only male deer grew antlers.
Male and female caribou (reindeer) can grow antlers. In other species of deer, antlers are normally only found on male deer. However, females can grow antlers if they have higher-than-normal testosterone levels.
In this article I look at why males have antlers and determine why female caribou are the only species to grow antlers regularly.
Why Do Deer Grow Antlers?
To Attract A Mate
Male deer grow antlers to attract a female deer for mating. When the antlers are growing during mating season, females will be shown a display, with each male trying to become the most dominant.
Males use their antlers for sparring with each other. They will also use their antlers as weapons to establish their dominance and compete for a female mate.
They also use antlers to rub against trees to show off their dominance. Males with the largest antlers are more likely to achieve the highest fertilization success and will obtain mates due to their competitiveness.
It is unknown whether this is due to the result of the display, male to male fighting, or due to the antler’s size and shape as this changes with some species.
The antlers are useful to protect deer against predators and other deer.
Sometimes when fighting other deer, the antlers can lock themselves together, causing the deer to starve to death.
Deer do not eat meat and are herbivores eating fruits, nuts, and acorns.
The antlers can be used to knock down fruit from trees. They also use their antlers to knock down acorns and nuts when in season.
Deer become hot in the summer, so they use their antlers in various ways to help them cool down and relax.
Deer use their antlers to create depressions in the mud or dirt, allowing them to lie down, relax, and keep insects off.
How does A Deer Grow Antlers?
The antlers grow from two base points on top of the deer’s head. These two points are called pedicles, and the antlers are bone tissue structures.
The velvet, a soft tissue, covers the antlers and feeds nutrients to the growing structure. The velvet contains arteries and veins, which are used to feed the nutrients.
Testosterone is needed to grow antlers, so the male deer with more testosterone is generally the one that grows them.
Testosterone in male humans plays a huge role in developing reproductive tissues and promotes bone and muscle mass characteristics.
The testosterone in the male deer is very similar and plays a key role in the deer finding a mate.
Why do Some Female Deer Grow Antlers?
Although the male buck produces testosterone, which is essential for antler growth, some female deers produce this.
An antlered doe rarely occurs because of an imbalance in the hormones that cause higher testosterone levels.
Some antlered does turn out to be hermaphrodites having both male and female sex organs, although these are rare, with estimates between 1 in every 5,000 antlered does.
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 the skull plate inside.
These defects are permanent antlers and do not shed like other deers. The Maryland Department of Natural Resources estimates that one female in every 20,000 does have small antlers.
Which Species of Deer Grow Antlers?
Deer native to North America all have antlers. There are two species of deer native to North America. These are the whitetail deer and mule deer. There is also a subspecies of the mule deer, the Pacific coastal blacktail, which also grows antlers.
The elk, caribou, and moose all have antlers, with the moose having the largest antlers. Antlers are grown from the age of one year old.
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. They are made of keratin on the outside, while 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 deciduou, growing each year.
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 cut off the blood supply to the antlers.
In early September, the velvet dries up almost completely 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 between 2 to 3 weeks. Between the pedicles and the antler, the tissue slowly disintegrates, causing them to come away gradually and then eventually fall off.
The deer will not have to wait long as new antlers will grow in the spring to prepare for the next mating season.
The length of time that a deer keeps his antlers before they shed depends upon his general nutrition and genetics.
Do Antlers Indicate Health Concerns?
The number of points on a deers antler is called the tine, and the amount can depend upon his health, genetics, how well he has fed during the winter, and his age.
Antlers do not always grow the same each year with different sizes caused by the deer’s health and food supply.
Because of damage over time from general wear and fighting, it is quite common to see deer with antler points that have been blunted or even broken off completely.