Those Things On Their Heads – Antlers Vs. Horns

Those Things On Their Heads – Antlers Vs. Horns

Those Things On Their Heads – Antlers Vs. Horns

10 minute read –

In our modern language usage, some terms or words may be incorrectly applied when describing an item. For example: some people do not always distinguish between horns and antlers where they incorrectly refer to all animal headgear as horns. Antlers and horns are very different in a number of ways and these variations are the result of millions of years of evolution and adaptation for the animal species to live a healthy life in the environment they occupy.

Bovids, or members of the horn-bearing group of animals versus cervids, or members of the deer, antler-bearing group of animals. 
Photo left to right:  Mountain goat, bison, moose, caribou. 
Credit: L.Caskenette & J.Paleczny

Headgear has influenced many aspects of some species and how they conduct themselves through the year; including the obvious breeding cycle but also their comfort in the heat of summer and how they communicate and identify themselves visually.

Let’s begin with construction materials: Horns are made from keratin- the same material as your hair and fingernails- whereas antlers are made from bone. Horns are a two-part structure. An interior portion of bone (an extension of the skull) is covered by an exterior sheath grown by specialized hair follicles called keratin.

Horns grow from the base where it attaches to the animal’s skull, antlers grow from the tips. Antlers are grown only by males of the deer species except for Caribou where females grow lightweight antlers, an adaptation for their grazing in snow for lichen. Horns are present on both male and females of most horned species with the males typically having larger horns than the females. 

Bovid family of animals have horns and both females and males with grow these horns. Typically female horn growth is smaller than males. Sexual selection plays a role here for large displays in both horn and antler bearing animals.

Perhaps the greatest difference between horns and antlers is that antlers are shed and regrow each year, where horns are permanent and remain and grow with the animal for all its life, or until they get broken off. Once they are broken, they do not grow back. The animal will carry a damaged or missing horn for the rest of its life.  Antlers also factor into the breeding cycles of the males who employ them to demonstrate their virility and to impress the females.

Antlers too may become broken or removed completely due to carelessness or fighting. These will grow back, but not right away. The animal must wait for the annual antler shed-regrow cycle for that year to conclude, usually in mid-winter before a new antler will form during the next year’s cycle, this may cause the animal to be without an antler for up to a year. 

Horns appear to form earlier than antlers on younger animals such as goats or bison, where Mountain Goat kids will be displaying small pointed black horns within a few short weeks of its birth, while antler buds appear at several months or so after a calf or fawn is born. But once they are in place and growing, they grow quickly.

Left to right: Mountain goat kids show horn formation, easily seen against the white; Watson the moose shows nubs of antlers developing in his first winter of life in 2019. Bison calves also show horn development early on in life. 

Antler is the fastest growing tissue of any mammal on the planet. With a healthy diet and high caloric intake, a moose can put on as much as a pound of antler in a single day. In the scope of just eight months’ growth, moose antler can grow from tiny buds as big as your thumb to gigantic antler racks measuring up to six feet across or 1.8 meters from tip to tip. A large moose’s antlers can weigh up to forty pounds or nearly 20 kilograms on average. Some very large moose antlers may weigh up to 75 pounds or 35 kilograms.

Credit Alaska News Source

Source credit: Alaska News Source

Back to construction for a moment; another key difference between horned and antlered animals is how the physiology of horns and antlers differ.

Horns have a central, conical bony core or cornual process that grows out from the frontal bone of the skull. On close examination of a horn you will see what appears to be layers of horn material (keratin) growing a new layer at the base which will grow longer over time and become thicker with subsequent new layers of keratin forming as the animal ages.

After 6 months of age, the bone becomes hollow and the space within it is continuous with the frontal sinuses. The surface of the bone is rigid and porous and is covered with an internal surface which keratinizes and forms the protective covering of the horn. The new horn produced at the base is soft and often transparent giving the horn a glossy appearance. Horn growth function is similar to how the cuticle on your fingers and toes produce the nails.

Source credit: Talmudology

Antlers however attach to the animal’s skull between the eye and ear at a place called the pedicel where they will grow to full size for that year over about eight to ten months. The antlers separate from the skull at the point of attachment, the pedicel.

Antlers separate from the skull at the pedicel, typically in the winter months.

The antler side is called the corona and forms a bone to bone connection with the pedicel on the skull that is remarkably strong until the its time to shed that year’s antlers. There is a chemical influence when the animal’s hormones change following the rut and seasonal progress that causes the bone between the corona and the pedicel to dissolve where eventually it weakens enough that the skull can no longer support the weight of the antler and it falls off. Both antlers may fall off at the same time, but it is common for both antlers to fall off over a couple of days.

Horns are mostly hollow, white antlers are made up of less dense, sponge-like bone called the trabecular that has been highly vascularized during formation allowing blood to flow to the tips of the antlers to facilitate their growth. Antlers require blood to grow while horns do not.

While antlers are covered in velvet, they are also engorged with blood which provides another important benefit besides growing the antler. As animals do not perspire or sweat in any way, they must expel excessive body heat by panting as many animals do. Antlers perform like radiators where body heat is expelled by the blood-filled antlers.

Ears of most deer species shed the fur and hair off them in the warmer months so they too can dissipate body heat. If they would let you, you could take the pulse of an antlered animal by finding a blood vessel on their fuzzy antler and placing your fingers on it to feel the beat of his heart. Don’t try this at home…or anywhere else.

Both horns and antlers have also been used by people since prehistoric times for tools of various kinds.   The hollow nature of horns has made them desirable for spoons, scoops and hand shovels or scrapers while the strength and hardness of antlers has often found them to be the material of choice for making hunting points for spears and arrow heads. Antler has also been a popular material for handles of tools like knives and axes.

Creativity and need, guided the early peoples to adapt and modify both horns and antlers for a wide variety of tools and other purposes to better their quality of life. They have often been used to make buttons for clothing or ornamentation. Antlers have been carved into needles for sewing of clothes, shelter and similar products, Horns were popular as gun powder containers as they would prevent the powder from getting wet and were easy to carry and measure the appropriate amount of powder into the firearm.

Yukon art Hints of Easter by Faye Chamberlain, 2021. Yukon Permanent Art Collection.

Both antlers and horns provide important functions for the animals that grow them so they may live healthy, secure lives. Their headgear has also influenced many of their social behaviors that have developed and evolved over the centuries. These include mating rituals and protective activities against potential predators.

Most of us have seen sheep rams rearing up on their hind legs and pounding their horns against another ram in courtship competitions, but they may use their horns to communicate in less violent ways. Rams may interlace their horns and gently rub ear to ear as a form of communication that we can only guess what it means.

Antlered animals also employ their antlers as a means to communicate for example when two young bulls will use their antlers to joust or push each other around like a game of reverse tug o war.

Antlers are also a means of displaying size and age which will determine their social order of who is dominant and who is subordinate. From a distance the size of the antler rack quickly displays the animal’s placement in the local social order, typically around the breeding season or rut when many male moose may gather in an area for an opportunity to breed with cow moose drawn to the area by pheromones carried in the wind.

Bulls with smaller antlers will size each other up based on their antler racks and determine their chances of winning a fight with a larger bull.

Animal headgear serves a number of important benefits for the creatures that grew them. Humans have also found inventive and beneficial uses for both antlers and horns once the animals are finished using them. Humans often use antlers and horns for tools, but they can also be transformed into wonderful works of art. Nature provides.

Doug Caldwell

Doug Caldwell

Wildlife Interpreter

Doug is one of the Interpretive Wildlife Guides here at the Preserve. An avid angler and hunter he has a broad knowledge of Yukon’s wilderness and the creatures that live here. With a focus on the young visitors to the Preserve, Doug takes the extra time to help our guests to better appreciate the many wonders of the animal kingdom here in the Yukon.

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The Antler and Breeding Cycle Featuring Moose

The Antler and Breeding Cycle Featuring Moose

The Antler and Breeding Cycle Featuring Moose

10 minute read –
Deer species are hoofed, ruminant mammals forming the family Cervidae. The primary deer species in the Yukon include: Moose –  the largest of the species; Caribou, Elk and Mule and White-tailed Deer which have migrated in from Alberta and British Columbia over the past 250 years, Mule deer are very well established with their range documented to extend up to the Arctic circle1https://www.britannica.com/animal/mule-deer.

Many of the Preserve’s visitors are fascinated by the antlers, held by members of the cervid family, and ask many questions about them. This article will explain some of the basics on the annual growth and shedding of the antlers and how they play a critical role in the breeding cycle of these animals. We’ll focus on the largest and arguably one of the most Canadian iconic members of the deer family – the moose and his antlers.

Cervids, or members of the Deer Family, grow antlers.  Only males grow antlers, with the exception of Caribou.  Photo left to right:  Caribou, Elk, Mule Deer, Moose.

Let’s begin when last year’s antlers fall off sometime in the mid-winter following the conclusion of the breeding cycle. The antlers separate from the skull at the point of attachment called the pedicel – the base. The antlers – a growth of bone that is chemically altered to fatigue when the animal’s hormones change following the rut, (a term for the breeding season), which also coincides with shorter days and less sunlight. The cast off of the antlers at the pedicle produces an open wound. Like any open wound there is some amount of bleeding, but it does not appear to be a concern for the animal, the blood clots and is washed off by precipitation and a scab like covering develops. 

Antlers separate from the skull at the pedicel, typically in the winter months.

After a couple weeks the new antlers begin to form, and it is not like a tooth where a replacement pushes the old one out of the way in order to grow, it follows a different process. A new antler bud grows in the pedicle of the animal’s skull. Soon after the antler bud has grown for a few days a soft fuzzy fur-like material forms on the bony bud. This is antler velvet and it is an organ. It contains blood vessels, capillaries and nerves that facilitate the growth of the antler over the coming months.

Velvet covers growing antlers:  it contains blood vessels and nerves to facilitate rapid seasonal growth.

While antlers are growing they are engorged with blood and are quite soft and delicate, so much so that the animal is very cautious to not damage their new antlers in any way. If they do become broken or damaged, the animal is stuck with the injured or malformed antler until the next year when a new set will grow after shedding the damaged one later in the present year. A damaged antler may also develop into a ‘non-typical’ antler where it does not match the one on the other side and is often considered a deformity. As an antler bearing animal ages there is a shift in hormone levels, just like humans, and this can manifest in antler deformities or increased ‘non-typical’ tines. As for humans, aging and hormone changes can mean greying hair or more brittle bones. These malformations can spell misfortune for a bull when it comes to successfully fighting off males and attracting females in the rut – we’ll get to that soon!.

Antlers can be damaged during growth; asymmetrical antlers can be the result.  This can spell bad luck for a male when it comes to successfully fighting off males and attracting females.

Antlers grow very quickly. In fact, they are the fastest growing tissue of any mammal. If the animal has a rich and voluminous diet, moose antler growth can mean packing on a pound each day2http://www.adfg.alaska.gov/index.cfm?adfg=wildlifenews.view_article&articles_id=175, in the form of bone of course. Coastal moose in Alaska tend to grow the largest antlers due to the quality and diversity of plants that grow in the temperate coastal areas of their rain forests compared to the colder and less vegetated areas inland like the Yukon. These full sets of antlers are often referred to as a rack.

Moose happily browse the aquatic and terrestrial plants they prefer as their new antlers continue their rapid growth. The high levels of sodium found in aquatic plants help moose antlers to grow quickly. Moose adapt to the additional weight and mass of their antlers and can be very exacting in their use for scratching. They know where each antler tip is and how to control their movements with great precision. One of the most remarkable examples of how well moose can control themselves with a large rack is their ability to walk through a forest and not make a sound as they weave their way through the trees with the equivalent of a kitchen table upside down on their head. They can also scratch delicate parts of their anatomy with an antler tip with little fuss.

Velvet hangs from antlers as bull moose browses aquatic plants in marsh at Yukon Wildlife Preserve.

Over the summer season moose continue to gorge on vegetation as their antlers grow within the velvet encasing them, then a number of changes take place as the autumn season approaches. The first frost and dwindling day light is a turning point and triggers a hormonal change in the animal whereby blood flows back into the animal’s body and stops flowing to the antlers causing the velvet to dry after a few days and become itchy. At the same time bulls that are reproductively mature experience other hormonal changes in anticipation of the rut.

The itchy antler velvet gets rubbed off on trees and the bulls do not look their best as ribbons of bloody velvet hang from their antlers. As they dry, the antlers grow hard due to the process of mineralization and result in a two-type cartilage and bone structure3https://www.msudeer.msstate.edu/growth-cycle.php. The inner portion is less dense, spongy bone that has been highly vascularized during growth. The compact outer shell of the antler is of greater density and is very strong and solid and will become the weapons used when fighting other bulls during the rut which is coming up fast.

Once velvet has shed, antlers calcify becoming strong and solid.  Males are now ready to challenge each other for breeding rights to females.

In preparation for the competition among the bulls (males) to breed a cow (female), the bulls announce themselves by urinating on their bellies or sometimes on the ground and then roll in the mud produced. The purpose of this is to get their scent or pheromones to be carried on the breeze letting the cows know where he is; his readiness to mate and making it easier to be found. Of course other bull moose smell this too and a number of them will gather in a common location on a mountain pasture and their mating fights begin as the bulls gather for the annual main event.

Bears, wolves and other predators also smell the moose pheromones and for them it is like the ringing of a dinner bell and they too gather nearby to take advantage of the situation that will soon unfold.

Elk males, like moose, may announce themselves by urinating on their bellies or sometimes on the ground and then roll in the mud produced

Bull moose stop eating when they go into the rut, partly because of the change in their hormones and also because they don’t have time as they are quite busy chasing other bulls away or fighting with them. Some moose can lose a substantial amount of weight when in the rut rendering them weaker and susceptible to greater injuries. Antlers can do some serious damage to other moose where an eye could be lost, a major organ could be pierced by an antler tip or many other injuries, such as muscle punctures could be sustained that would make it much easier for a grizzly to be successful in it’s hunt for food. That’s why predators hang around the rutting areas, it often results in injured moose bulls that are easier to overtake due to their wounds.

When the cow moose go into estrus or heat, they are only then ready to be bred. Some documentary TV programs elude that it is the bulls’ fighting prowess that determines which bull gets to mate, that may be true but it is not the only consideration. The cow still selects which bull she will mate with and it may be the result of the fights, or the appeal of the bull’s pheromones or other factors we are unaware of. But her goal is to produce the best offspring possible and how she makes that determination is her business. The cow will only breed once, while the bull’s goal is to breed as many cows as he can.

Once all the breeding is concluded, the cows and the bulls go their separate ways and will remain isolated from each other until next year’s breeding season occurs again. During this time, the bull’s antlers fall off and the antler cycle starts all over again.

Cow moose may give birth to a single calf or twins and sometimes triplets in the late spring after the ice and snow have turned to water once again. The bulls wander independently between the low river valleys and the mountain tops browsing while their new antlers grow as they evade predators until the rut calls them back to that special place where the breeding games begin anew.

Doug Caldwell

Doug Caldwell

Wildlife Interpreter

Doug is one of the Interpretive Wildlife Guides here at the Preserve. An avid angler and hunter he has a broad knowledge of Yukon’s wilderness and the creatures that live here. With a focus on the young visitors to the Preserve, Doug takes the extra time to help our guests to better appreciate the many wonders of the animal kingdom here in the Yukon.

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Swipe Right (for Antlers)

Swipe Right (for Antlers)

Swipe Right (for Antlers)

Only animals in the deer (or cervid) family grow antlers. That includes elk, deer, moose and caribou.

Animals like Bison, Sheep and Goats are part of a different family and grow horns, not antlers. We’ll tackle that in another video/post!  With the exception of Caribou females, only Cervid males grow antlers, mostly to attract attention from females. 

Antlers are also really important for determining which males will get to breed – this is established through posturing and challenging other males of the same species to duels. 

Antlers grow, and fall off (or shed), every year. Depending on the species and the individual animal, antlers fall off anytime between the end of December to April. This leaves a “kind-of” scar on the animal’s head, called the pedicle – this is the spot where the antler meets the animal’s skull. From that “scar” – or pedicle, the new antler starts to grow – and it is covered in a fuzzy brown skin we call velvet.

 

This photo was captured just moments after the antler shed. The blood is from little bits of dried skin around the pedicle that was attached to the antler. The antler that detached was a pure white bone – no blood. Photo by Jake Paleczny.

The new antlers basically start growing immediately. Within a couple weeks the pedicle will have little fuzzy bumps. Photo by Lindsay Caskenette.

That velvet has nerves and blood supply bringing in nourishment to grow those antlers, which are soft at this point of growth. Antlers grow very quickly and in the Yukon, antler growth is typically done by early to mid-August. Antlers take an ENORMOUS amount of energy to grow. Only the healthiest animals will have impressive antlers.

Once they’re done growing and have fully calcified (or hardened) the blood supply to the velvet stops, the velvet dies and the animal may rub that off on stones/trees or it just falls off.

Because the nerves also die with the velvet, the antlers now have no sensation and are ready to challenge other males to duels, and hopefully impress the females. Antlers can be an important part of asserting dominance.

Female cervids can look at a male’s antlers and have insights in to their diet, nutrition, overall health and of course, genetics. Large, symmetrical antlers say healthy genetics and that means healthy babies.

A female might be impressed – “you grew those antlers in just ONE season?!?” or – she might not be impressed.

Either way, once the breeding season is over, and winter is on its way – hormonal changes triggered by reduced daylight causes the pedicle to begin deteriorating which eventually causes the antler to break away from the weakened pedicle, the antlers will fall off and the cycle renews.

Julie Kerr

Julie Kerr

Visitor Services Coordinator

Julie is a Registered Veterinary Technologist, living and working in Whitehorse since 2012. She joined the team in May 2018. She is passionate about wildlife, nature and living in a conscious manner with both. Her free time is spent outdoors observing wild animals and ecosystems; her connection to the natural world around her brings great joy – joy she loves to share with anyone interested. Honestly? Work and life blend rather seamlessly.

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Bull On Encounter!

Bull On Encounter!

Bull On Encounter!

Right place right time! Animal Care Assistant, Bree Parker spends day after day diligently supporting our veterinarian Dr. Maria Hallock in caring for, feeding and ensuring the well-being of our collection of wildlife residents. 

Equally as important and valuable as literally providing food for the animals also is observing the animals. Observation is a critical part of our animal care process. This is when staff ensure an individual animal’s behaviour is normal. Observing them eating, moving and interacting helps us know that animal is content and full-filling life needs. Signs something is off can include: the animal has a limp; they are not coming to the feed stations and eating; or, they are not socializing in a typical  herd group. These observations could indicate that there might be an ailment to the individual that deserves closer observation or possibly even intervention. However, sometimes this observation can be quite enlightening, it can catch incredible moments of animal encounters and wild behaviours we strive for our individuals to be able to fulfill.  

We’ve been waiting for the young bull to drop his antler for months now. . .

Bree starting filming this interaction simply because she thought it was fascinating and humorous to see the younger bull (on the left) asserting dominance with another bull, an older bull, with no antlers. Then everything got pretty exciting, pretty quickly!  “We’ve been waiting for the younger bull to drop his antlers for months now. The older bulls lost theirs in December” said Bree.

This is typical to have individuals vary on antler shed timing, especially between different aged individuals related to sexual maturity. Over the next several months both these individuals, along with all our antler-bearing cervid’s (like moose, elk and mule deer) will be re-growing their antlers in preparation for fall. Alas, as another rut season comes and goes, so too will their antlers!

Bree Parker

Bree Parker

Animal Care Assistant

All animal lover to her very core! Bree has had a menagerie of pets over the years, including mice, crayfish and a hedgehog. After completing her Environmental Technician diploma at Seneca College, she realized her true calling was with animals, sending her back to Ontario this coming fall for University of Guelph Ridgetown Campus’s Veterinary Technology program. Bree is always eager to learn new facts about the animals at the Preserve that she can share with visitors.

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