Thinhorn Mountain Sheep

Thinhorn Mountain Sheep

Thinhorn Mountain Sheep

10 minute read –
For a long time, it was believed that there are three distinct subspecies of thinhorn Mountain Sheep in North America each of these known as: Dall, Fannin and Stone. Each subspecies displayed different colouring of their coats where Dall would be pure white, Fannin would be white with grey, silver and black highlights and Stone sheep were white with brown and black highlights and sometimes predominantly all dark grey.

Thinhorn Mountain Sheep grow one set of horns from youth to old age.  Pictured are two rams (males).  L to R:  Young ram; mature ram.

Recent DNA gathering and analysis has revealed that all three subspecies are actually very much alike and identification of each subspecies is becoming significantly more difficult to confirm as interbreeding continues and identifiable traits or genetic markers blend together to produce a mongrelized modern day specimen.

Further, evolutionary biologists1https://www.ualberta.ca/science/news/2016/june/dna-analysis-rewrites-the-story-of-thinhorn-sheep-during-the-last-ice-age.html studying the lineages of thinhorn sheep have found evidence suggesting that the species diverged hundreds of thousands of years earlier than previously thought. Greatly influenced by the formation, movement and final melting of the glaciers, thinhorn sheep roamed a vast area in search of ice-free grazing areas known as refugia. The mountainous geography often separated groups of similar or same subspecies sheep where through isolation they accumulated some variances between populations over time, sometimes resulting in the formation of what were originally thought to be new subspecies due to variations of their physical appearance.

Genetic science continues to study these animals and new proofs are foreseen to reveal how the present thinhorn sheep populations of the Yukon, BC and Alaska evolved to be what they are today. As genetic scientists work with data gathered by paleontologists, geologists and other scientific disciplines, there is anticipated to be a more accurate understanding of how northern animals evolved into what they are today.

Despite their uniqueness in genes and variations in colour, thinhorn sheep rams share the same impressive set of horns that are admired in the animal kingdom. It is important to note that horns and antlers are not the same. Members of the deer family grow antlers which are shed and grow back each year, while sheep grow horns which are with the animal for all of its life. Also antlers grow from the tips while horns grow from the base.2https://medium.com/usfws/11-facts-about-antlers-18e689fe9e60#:~:text=Bison%2C%20antelopes%2C%20sheep%2C%20goats%20and%20domestic%20cattle%20%E2%80%94,from%20the%20tip%3B%20horns%20grow%20from%20the%20base  It’s a minor thing, but important because if a young sheep breaks off a tip of their horn, it will remain that way for the rest of its life. Female sheep or ewes also grow horns but these are much more diminutive than the male sheeps’ horns.

​ Female sheep or ewes also grow horns but these are much more diminutive than the male sheeps’ horns.

Sheep start to grow their horns shortly after birth and they will continue to grow over their lifespan, sometimes up to 20 years of age.3http://www.env.gov.bc.ca/wld/documents/thinhorn.pdf If you look closely at a ram’s horns you’ll see rings that circle the horn in various locations. These are called growth rings or annuli rings and a new one is formed each year and they are a reliable method to estimate the age of the animal. The horns are made of keratin, which is the same hard material that their hooves are made of and it grows quickly.

The first few inches of horn that a ram grows is called a lamb tip and represents about the first 6 months of the animal’s life,4https://www.adfg.alaska.gov/static/hunting/dallsheephunting/pdfs/dall_sheep_guide_to_judging_sheep_horns_under_full_curl_regulation.pdf it often gets broken off as the ram’s life of fighting and careless use take their toll.

Credit Alaska Department of Fish and Game
Each year a new annuli ring is formed near the base due to stressors the ram experiences, normally associated with the mating season.  You may notice that the space between the annuli rings is not uniform. This reflects the quality of nutrition that the animal experienced during that year of his life. Large wide spaces between the rings indicate good nutritional intake and low stress. Small thinner spaces may indicate a stressful year or a reduction in nourishment possibly associated with long, hard winters, forest fires and a loss of grazing, avoiding predators and similar stressors found in nature. Once the ram reaches a certain age of maturity, at about eight years,5https://www.coniferousforest.com/dall-sheep.htm the horns will continue filling out in thickness and mass, but stop growing longer as time goes on. A mature ram’s horns can weigh up to 15 kilos – more than all the bones in his body combined.
The size and shape of ram’s horns are what distinguish it from others and there is a wide variety of shapes, formations and sizes among sheep horns. Some horns form concise symmetric circles that are located close to the animal’s head, while others grow into a cork-screw-like shape where the tips are splayed out from the ram’s head. Some rams have horns that are thicker and longer than others, this is normally associated to a genetic trait of the animal’s ancestors where the influencing genes get passed to subsequent generations.
Hunting organizations such as Boone & Crockette have devised an elaborate measuring system with which to score the horns of most big game animals. The horns are measured at specific locations including the base, the overall length of the horn on each side, the distance between the horn tips and diameters of the horn in four key places. Once these measurements are collected some math is performed to arrive at the score for that ram’s horns. Records are kept by species so that hunters know how their harvested ram compares to others. This record keeping is also valuable for biologists and others to track the various changes in sheep populations around the world and may indicate declines in health, and their supporting environment and other influences which may be indicated by the changing size or condition of their horns.

Regional governments also utilize hunters to gather important data from the field. This is usually done by making it mandatory that certain parts of the harvested animal are submitted to the Game Branch as a condition of the species harvest tag. In this way biologists get to examine a diversity of a certain species all harvested within a quantified period of time and noted locations. Biologists examining sheep submissions here in the Yukon check for a number of important indicators. Yukon regulations require the complete head of a harvested ram be submitted for inspection.6https://yukon.ca/sites/yukon.ca/files/env/env-yukon-hunting-regulations-summary_en.pdf]]

The first thing they examine is if the horns are indeed a full curl as regulations prohibit harvesting a ram that is less than a full curl.

The biologists then extract a tooth to confirm the exact age of the animal by cutting the top off and counting the rings similar to the dendral or age rings of a tree. They may also take a tissue or blood sample to test for various diseases and infections the animals may suffer from. When all the tests have been completed the biologist bores a small hole in the top side of the horn facing the rear and epoxies a serialized aluminum plug into it. These plugs help to combat the underground trade of animal heads by having each head recorded by hunter, date and location.

Having access to all this data helps biologists to better understand the health of the wild sheep herds and may provide clues on where a disease is developing and which way it may be moving geographically.

Photo Credit: Kevin Pepper

Photo Credit: Kevin Pepper

Rams are famous for bashing their horns together to determine which is dominant for breeding purposes, but that is only for a few days each breeding season typically in late November and December. They also use their horns to communicate among themselves in ways that humans can only guess at. They will sometimes interlace their horns gently and rub their ears together which appears to be a welcoming gesture. Like most creatures, mountain sheep use body language to communicate with others. It may be a twisting of the head or extending their noses while they peel their lips back to reveal their teeth, or something as simple as their stance and how they wiggle their ears as they stare at others from a distance. They often grunt at each other as well.

Rams will often gently head-butt  each other as a form of greeting, similar to how a house cat bumps your leg when seeking attention. They can be quite gentle in their horn touching activities or they will get up on their hind legs and really lean into butting another ram with all the force they can muster.

Photo Credit Mark Newman

Photo Credit: Mark Newman

With remarkable muscle tone, balance and coordination mountain sheep demonstrate how well they have adapted to living on rock faces as they frolic and cavort in situations humans try to avoid. Often it will take a human significantly longer to cover a vertical climb it only took a few seconds for the sheep to navigate. Mountain sheep are remarkably strong and have endurance that allows them the energy and stamina to evade predators such as wolves and bears on the uneven and precarious mountain slopes they call home. Young lambs are a popular target for migrating Golden Eagles arriving in the spring season from their over-winter habitats. So sheep must be watching in all directions for potential dangers that could impact on them or their offspring.

Young lambs are a popular target for migrating Golden Eagles.  Ewes must be watching in all directions for potential dangers that could impact them or their offspring.

Mountain sheep have superior eyesight for distance and low-light conditions, they have horizontal pupils that help them to see panoramically to detect predators that could approach from different directions.  They also need to be able to see forward clearly so that they can run over rough terrain. They have excellent peripheral vision and can see behind themselves without turning their heads due to where their eyes are located on their skulls. Remember they need to look around their horns too.

Thinhorn Mountain Sheep are remarkable creatures perfectly adapted to thrive on the mountains of Northwestern Canada and Alaska and will remain a featured megafauna species here at the Yukon Wildlife Preserve.

Ram follows an Ewe closely.

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.

Explore by Category

Explore by Author

Faces of the Preserve:  Maureen

Faces of the Preserve: Maureen

Faces of the Preserve: Maureen

12 min read –
It takes drive and passion to support a non-profit organization which works to be a living center of Yukon’s wildlife, with informed voices that speak for, and connect others to, the natural world. Who is the team making this happen?

Meet Maureen. She’s a Yukoner with a rich and varied history – just like Yukon Wildlife Preserve. Here she shares what she loves about the Yukon, working as a Wildlife Interpreter, and how that happened in the first place.

“I had always wanted to visit the Yukon. I moved to Whitehorse in 1970 and knew from the start this would be home. In 1973 I moved even further north, to Dawson City, and have spent the next 50 years between the two communities.” As many Yukoners know, successful longevity in the Territory can require versatility; Maureen has this in spades. She joined the team in 2013, drawn to Yukon Wildlife Preserve through a combination of knowledge and understanding of animals, Interpretive experience, and an enjoyment of speaking to people.

Whether in her fox scarf, or her fun moose toque and Covid-19 mask, Maureen helps guests learn about animals.  L to R: Maureen shares knowledge about Wood Bison; Maureen teaches about moose; Guided Bus Tour guest enjoys a close up of Bison while listening to Maureen.

“For 20 years I worked as a commercial fisher(wo)man on Yukon River and Lake Laberge. I spent 30 winters as a trapper, operating from a cabin with no electricity and no running water and 10 years as a placer miner. Finding prehistoric bones while placer mining, that’s very interesting – the most interesting part of placer mining in fact. I have always had an interest in archeology, turns out I had no interest in gold via placer mining! Finding bones:  that’s an immediate link to history and the land. Combined, these are years of experience which had me on the land and water, harvesting, observing and getting in tune with nature, the seasons and animals. I learned a lot, during those years, about animal life cycles and respect for animals. I would say I have more appreciation for wild animals because I understand more about how hard life is for them.

I’ve worked for Parks Canada as an Interpreter for 25 summers at sites such as Dredge #4, Bear Creek, Dawson City walking tours and SS Klondike. I’m a Certified Interpretive Guide with the National Association of Interpretation. All those years talking to people, connecting them with history and the Yukon; I bring that to Yukon Wildlife Preserve. My appreciation for and understanding of wildlife, in addition to my skills of observation learned from my years living and harvesting on the land, really assist me in helping to connect our visitors to Yukon species. Specifically, my tracking skills help me observe wild animals in their natural habitats, as well as to understand the story of what I’m watching them do, in that moment. I enjoy sharing those skills and helping visitors learn how to “see” animals that are excellent at camouflage and how to take that beyond their visit to the Preserve, to their lives at home, wherever that is.

Visitors sometimes wonder how my years trapping, hunting and fishing can mean I have a strong appreciation for wild animals. I try to explain that I think I have a greater appreciation because of my experiences, because when you live in the bush, you live closer to the animals. Not only do I think I understand more about how hard life is for wild animals, but I depended on them for sustenance and my livelihood. This has allowed me to acquire a greater appreciation for wildlife. Living this close to nature, while raising a family, allowed me to pass on to my daughter how to observe animals, their natural behaviours and to listen to what their body language and actions are saying, and to then change my behaviour accordingly. We don’t have to speak the same language as animals to hear, and respect, what they are telling us. Humans, we learn that, and I’m pleased to have been able to pass on those teachings to the next generation.

I remember I once had a curious porcupine sit and talk to me, chattering on with its porcupine noises. It was very engaging, although I didn’t understand a word. I finally had to tell the porcupine that I had to leave to do other things that day, and I was the first to leave the conversation.

Trapping and hunting has taught me to pay attention to the animals themselves, and to the signs they leave behind:  tracks, scat. The only way for me to be successful was to observe all these things within a species, and within the area I was harvesting. You have to know your area and the animals on it. You become part of a system when you’re harvesting off the land. You are a predator, and like wild predators, you don’t take all the prey out of your area. As a trapper and subsistence hunter, I participated in a relationship with the land, the animals and the environment; this allowed me to become in tune with the rhythms of life around me. There’s a balance within nature, if we noticed a shift in that balance, then we shifted to accommodate it. Yes, there were parts of this life that were hard and challenging, but it was also rich and rewarding – and very much a lifestyle choice.
I lived 30 years in a cabin in the bush. I stopped trapping and moved back to Whitehorse in 2009, because I like running water and electricity. While I miss the quiet of that life in the bush, well I LOVE the ease of modern life. After so many years without, I don’t take for granted things like lightswitches, kettles, showers or flush toilets. Living without for so long, that’s a hard life. Hauling water, in the winter, by buckets out of a frozen river means chopping holes in the ice with chainsaws or axes, and then doing it again when that hole inevitably refreezes solid. It really puts you in tune with the harsh realities of life and survival; I think it has helped me gain understanding and insight into some of the challenges wild animals face daily. They can’t just flip a switch or push a button and get food or shelter, they have to work hard, and constantly, to be successful in life at acquiring food, territory, shelter and to be successful at breeding and rearing young.
My favourite animal in the wild is the Lynx. They’re cool and simply the most beautiful animal. In the area I lived in the bush, lynx were rare and sightings were very special. Once, I heard a lynx scream. I’ll never forget that sound, or having to keep my dog under control to avoid him going to investigate. Here at the Preserve, my favourite animal is the Muskox. They are survivors and they are stubborn. I respect both those qualities. I’ve been in the Yukon a long time, but I’ve got nothing on the tens of thousands of years of Muskox. They’ve been stubbornly surviving since the last Ice Age.
Visitors to Yukon Wildlife Preserve, they are often curious about more than the animals at the Preserve. I enjoy the opportunity to connect with people of all ages. Some people want to listen, some ask a lot of questions or share their own experiences with me. No matter how or with whom the connection, I enjoy it most when people are interested and open to learning about respectful interactions with wildlife and the land.

Respect, observation, space, quiet, an understanding of the behavioural norms of the different species we can encounter:  this leads to successful interactions with wild animals – safe for us and safe for them. Animals don’t speak human languages, but they don’t need to. Humans can pay attention to the body language of an animal to hear what that animal is saying to us, and if humans don’t know how to do that, we can learn. I try to relate how to do this to visitors to Yukon Wildlife Preserve, and to teach those who are willing to learn.”

Maureen has had guests on her tours ask if she was a schoolteacher. “I was not a teacher.  To me, education sounds like sitting in a classroom. Instead of offering education, I prefer to think that I am helping people learn about the things I know about:  animals.”

Maureen is one of a strong community at Yukon Wildlife Preserve and part of a thread that weaves us together. The next time you visit, stop at the Reception Cabin and say hello, or share a story:  you might just learn something new from Maureen. “I hope that after I’ve talked to visitors to the Preserve, that they leave with a little more knowledge and understanding of the wildlife they might encounter. Also, a little more respect for those animals.”

Stories by Maureen Peterson.  Compiled and written by Julie Kerr.

Maureen Peterson

Maureen Peterson

Wildlife Interpreter

Maureen is originally from North Vancouver, BC, where she lived for the first 20 years of her  life. In grade 5 she did a project about the Yukon, which is when she decided to go there. It was at age 20, and the day after she was married, that she finally moved North.  The Yukon was everything the 10 year old Maureen thought it would be and she has never had any desire to move anywhere else.

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.

Explore by Category

Explore by Author

Misunderstood Moose

Misunderstood Moose

Misunderstood Moose

5 min read –

You have most likely heard the phrase “Don’t judge a book by it’s cover”, implying that captivating stories can be hidden behind bland book covers. Similarly, at one time or another many of us have been judged or have judged others based on their outward appearance. Judging others based on their appearance can lead to us underestimating other people’s abilities. Have you ever been underestimated? How did it feel? Due to their funny-looking, long snouts, and gangly, plodding bodies, moose are often underestimated. People tend to view moose as gentle, slow-moving animals, and often don’t associate moose with characteristics such as agile and fierce. Cartoons1Like Bullwinkle the Moose can perpetuate this impression by displaying moose as slow, friendly Canadians. But don’t be deceived by this common misperception. Though moose may look unassuming, they are capable of performing impressive athletic feats in order to find food and avoid predators.

Despite their appearance, moose can easily propel themselves through water in order to find food. While otters, beavers, and other mammals that are known for their swimming ability have lean bodies and webbed feet which allow them to easily glide through the water, moose are heavy-set and have hoofed feet. Despite their size and hooved feet, moose have the advantage of being tall, and their long legs help propel their large bodies through the water. Moose also have hollow hairs, which help them stay buoyant while swimming.2National Park Service With these advantages, moose can swim as fast as 9.5 km per hour. By comparison, most humans only swim at the pace of 3 km per hour. Moose’s ability to swim quickly allows them to travel in search of food while reducing stress on their joints. Water also helps protect moose from predators because it is more difficult for predators to sneak up on them when they are in the water.3Moose Facts 

Moose swimming across Lake Laberge.  Photo credit D. Caldwell.

Photo Credit Johanna Marglowski

Moose also have adaptations that allow them to dive underwater to eat nutrient rich aquatic plants.4National Geographic To prevent water from rushing up their noses, moose have flaps that close in their nostrils. These flaps allow them to hold their breath underwater for up to 50 seconds5Holding breath Ecology and Management of the North American Moose and help them to dive up to 6 m (20 ft) underneath the water surface!6Hinterland Who’s Who After a winter of sparse food resources, aquatic plants provide essential energy to both pregnant cows (female moose), and to bulls (male moose) as they regrow their antlers.

In addition to swimming, moose are also capable of running at high speeds. Being the tallest member of the deer family, a moose can stand around 6 feet tall at the shoulder, which is as tall as some professional basketball players.7National Geographic Even though moose might be too gangly to make great basketball players, their height and long legs allow them to run very fast. A moose calf can outrun the average human after only 5 days of life,8National Geographic while an adult moose can charge at a pace of 56 km per hour, and maintain a pace of 32 km per hour over longer periods. For perspective, during his world record 100 metre dash Usain Bolt ran at an average pace of 44 km per hour. However, moose do not run fast to set world records, their speed provides them protection by enabling them to run away from wolves and other quick-moving predators.

Furthermore, despite the perception of being friendly, moose are actually effective fighters. Though they sometimes use their speed to outrun predators, an experienced and healthy moose is capable of defending itself against wolves by standing its ground and fighting.9Wolves of the Yukon by Bob Hayes Moose will protect their sides by standing next to trees and high shrubs, and then use their powerful legs to stomp or kick attacking wolves, hitting them with their deadly hooves. A powerful strike from a moose’s sharp hooves can result in injury to or even kill a wolf. 

Even young moose are large animals.  The photos show 2 moose bulls; on the left a young 1 year old and on the right a more mature bull of many years of age.

So, are moose really the plodding, polite animals that cartoons depict them as? Have you ever underestimated moose based on their goofy-looking appearance? As we have seen, instead of being slow, and plodding, moose are impressive athletes. Moose are capable of swimming through and under water, which allows them to more easily travel in search of food and access the nutrients they need during pregnancy and to grow antlers. Moose are also capable of running at high speeds and of fighting off other animals, which helps them survive attacks from wolves and other predators. Each of these athletic capabilities are important survival mechanisms that help moose thrive in the wild.

Tasha Mazurkewich

Tasha Mazurkewich

Wildlife Interpreter

Tasha is a self-proclaimed animal enthusiast and adventurer. Originally from British Columbia, she enjoys skiing, hiking, and all things outdoors. She is happiest when she is climbing a mountain with her pup. Having recently moved up north, she has enjoyed learning about Yukon’s wildlife and landscape and is excited to share the new knowledge she has learned with visitors to the wildlife preserve

Explore by Category

Explore by Author

Fall In to Autumn

Fall In to Autumn

Fall In to Autumn

5 minute read – 
Autumn is a season of change! It’s the bridge which helps us transition from summer towards winter. What a beautiful bridge it is, with leaves blazing colour in vibrant hues of red, orange and yellow. Fireweed has flowered and the leaves are crimson. Against this backdrop the first snows fall on the mountaintops.

Birds begin their migration back to their southern overwintering grounds, after a summer spent mating, nesting, rearing young, and eating well. Before we see the V’s flying overhead, we often hear them honking and calling to each other.

In the world of ungulates, it is the time of the rut. Antlered animals have finished growing this season’s antlers; their velvet has sloughed off and now they sport their hardened, ready-to-duel finery. We can see and hear as the males clash, challenging each other for the right to breed the females. Elk stags bugle, bull moose softly grunt – calling to interested females in the area and warning off competing males.

Watson, in the foreground, has shed the velvet on his first year’s full antler growth.

Those with horns are also clashing. This looks less like a duel and more like a train crash. Thinhorn Mountain Sheep rams, both Stone and Dall subspecies, run at each other and smash heavy horns together – the echo of this collision ricochets like a rifle shot. Muskox bulls have been rumbling since early August, chasing each other, establishing dominance and finally banging horns as they work to impress the females for breeding rights.
We begin to notice a lack of Arctic Ground Squirrel activity. We no longer hear the constant shrill warnings as nearby predators hunt; where are these industrious rodents? Hibernation comes early – females are already underground for the long winter ahead, and the last of the males aboveground continue to harvest and stockpile their midden, into early October. Predators such as Red Foxes can be seen traveling from one burrow-entrance to another…..looking for a disappearing meal of ground squirrel which used to be in abundance. Soon they’ll be gone completely, hibernating through the winter, under a thick layer of blanketing snow – but not just yet.

Autumn means hibernation is coming.  We’ve noticed a lessening of Arctic Ground Squirrel activity at Yukon Wildlife Preserve.

Humans are adding clothing layers, finding sweaters, mitts and toques in storage. We need these warm additions on the crisp, cold autumn mornings. Afternoon sunshine heats up; we turn our faces to the sun and shed those layers – it’s not winter yet! So too are the animals growing coats of winter fur, wool and hair. Mountain goats have spent all summer shedding last winter’s wool; almost immediately it’s time to grow in this winter’s layer of hair. Arctic Foxes are beginning to add some white to their brown and grey camouflage. They not only change colour with their winter fur, they also add seeming bulk. All those layers of white fluffy fur help them stay warm, maintain body core temperature and thrive in the harsh winter environment of the Far North.
Enjoying this short season is highly recommended – there’s nothing as seasonally relevant or celebratory as jumping into a pile of autumnal leaves. Cranberries are ripening, harvesting continues. Underneath the beauty of the changing season, there is a sense of urgency. Whether we are human or animal, we know winter is coming, and while it’s not here yet, time and opportunity are limited to eat, put enough weight on, or store food to survive the coming months.

Summer is over, the cycle continues. Autumn is the clear signal to prepare for what’s ahead. Fall in to Autumn; experience the sights and sounds with enjoyment, wherever you are.

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.

Explore by Category

Explore by Author

Mountain Slopes – Yukon Wildlife Preserve

Mountain Slopes – Yukon Wildlife Preserve

Mountain Slopes – Yukon Wildlife Preserve

11 min read –
The Yukon Wildlife Preserve features eleven iconic northern animal species, but if you look closely at each of the three primary habitats on the Preserve you’ll see many more species than “only” eleven. The three primary habitats include: grasslands, wetlands and mountain slopes. Each of these habitat types support animal and plant species that have evolved together over millions of years resulting in communities where they all make a living and contribute different values to the continuing health of their specific habitat. In this three-part series we’ll review each habitat and examine the greater community it represents, concluding with mountain slopes.

Mountain goats on their cliff habitat at Yukon Wildlife Preserve

Looking around the local landscape we easily see the topographic differences near to us and in the distance. These elevational changes of the geography influence how animals move, reproduce and make a living. Some have evolved physical adaptations providing them with advantages to live in different habitats compared to other species.

Some creatures have evolved to live on the rock faces of mountainsides, while others are better equipped to live in the valleys often near rivers and other water bodies. Some other species can live easily on all land types, like the Caribou that often travel great distances over all types of terrain along their migration paths.

 Caribou often travel great distances over all types of terrain along their migration paths.

The land all around us is in a continual state of change as it has been since time began. The Preserve is located within the Takhini River Valley. The river is south of us, only a few hundred meters away. Glaciers filled this valley up until about thirteen thousand years ago. While they were here, the glaciers altered the landform in some very dramatic ways as they bulldozed great areas of soil and rock, gravel and forested areas resulting in what we can see today. Look at the mountain tops across the valley and you’ll see the smooth rounded tops where the glaciers ground them down; and the other mountains with jagged and pointed tops indicating where the glaciers did not have a similar impact because they did not grow that high. However erosion is still at work as the influences of wind, rain, ice and snow continue to alter the landscape.

This type of landform provides a spectrum of variables that influence the safety, nourishment, and rearing of offspring that many species have adapted to over thousands of their generations.

Going back millions of years, many species evolved due to the influences of what they prefer to eat and where that food source could be easily found throughout the year. For example, beavers depend on wooded vegetation and while trees grow on mountain slopes, beavers had greater opportunity and benefit to feed on the vegetation that grows next to waterways, so beavers evolved to be more adept at swimming and thriving in an aquatic environment that also sustains certain species of trees that beavers adapted to thrive on.

Mountain Goats and Sheep are the megafauna species featured in the rocky habitats here on the Preserve, They evolved specialized hooves and muscle groups to allow them to move quickly, and safely, on the various rock types found on these slopes.

Of course there are numerous other species present here as well and while they have not evolved noticeable physical adaptations to live on the rocks, they have learned how best to live in this habitat and find the resources required to raise a family and make a living. Our ever-roaming foxes are often seen walking among the goats on the rock faces in their never-ending search for food. Many birds will nest on rocky crags and outcroppings as the precarious nature of these do provide some level of protection against predators like the fox. Eagles, hawks and owls often select a high perch on the rocks as they scan the area looking for their next meal. They often build nests in the protected areas in a crack high up a rock face to take advantage of these lookout positions.

Golden eagle nest on Lake Lebarge’s eastern shores early 2000’s.  Photo D. Caldwell

Rodents also make their homes within the jumbles of rocks hoping they have chosen a safe place to raise a family. Members of the weasel family, including Pine Martin, mink, weasels and even the cunning Wolverine will seek a suitable place to den among the rock slides as well as the forested areas nearby. Bears of course also seek out suitable places in the rocks to den and hibernate over winter.There are no bears denning on the Preserve at this time that we are aware of.

Also not present on the Preserve, are other creatures like Marmots and Pikas that typically make their homes high up in the rocks and mountains of the Yukon, Some species seem to be very widespread and can be found in a variety of Yukon habitat types. While some others are localised to specific geographic locations or elevations where they have the greatest opportunity for success. The ubiquitous Arctic Ground Squirrel also favours mountain sides to make a home.

Keep in mind that numerous natural influences like wildfires, landslides, avalanches and similar disruptions may alter the living conditions for a number of animals that will need to go in search of a new home to raise a family. The same may happen when a grizzly bear selects a den near a favoured grazing area of sheep or goats. To remain safe, the sheep will seek out a new grazing area well away from predators and other dangers.

Thinhorn Sheep rams enjoy sunshine in their predator-free grazing grounds at Yukon Wildlife Preserve.  In the background we see the sheep-accessible cliffs within their habitat.

Rocky habitats are not without their dangers. During the winter season ice will form in small cracks and crevices within the rocks, as the ice becomes colder and swells it further fractures the rock sometimes making it dangerous in that it may break away completely and fall further down the slope.

Gravel screes are the deposits of smaller rocks, pebbles and dirt that have fallen from above and form a skirt of loose materials at the base of a rock face. These can be difficult for mammals to walk on quietly and safely and as such provide another level of security for the creatures that dwell on the mountainsides. Flash floods caused by voluminous rainfall and spring snowmelt can also be dangerous for the creatures that live on the rocks.

Rocky habitats are not without their dangers, which change based on the season.  Here, Thinhorn Mountain Sheep walk through deep snow along the cliff edge at Yukon Wildlife Preserve.

Because rocks warm in the sun and hold that warmth after the sun sets, some rock faces are preferred by early arriving bird species, like raptors, that will nest there to get started on raising the offspring that may hatch while snow still lies on the ground. Raptor parents teach the offspring how and where to hunt after they have learned to fly. They have lots to do within a short seasonal weather pattern, so nesting in the warmth of the rock faces provides them with an advantage to raising a healthy next generation.

Like all other habitats on the Preserve, winter brings some profound changes to mountain slopes the animals must literally take in stride. The goats and sheep cannot run and frolic on the snow covered rock faces as they do in the ice-free season. They pay closer attention to where they travel and may use alternate trail systems during these times to prevent slips and falls. They still make it look much easier than it is and they sometimes look quite smug as they look down at us staring up at them from the road.

The spring thaw also introduces new dangers as the warming rocks may cause the ice to melt from beneath, creating loose patches that can break away when a foot is placed on them. Meltwater cascading down the slope is another seasonal hazard the creatures are well conditioned to avoid. Staying warm and dry is its own reward when the chill winds blow high up on the rocks.

As the ice and snow melt away and the winter white gives way to the browns and greens of spring and the migratory populations return for another summer in the Yukon, the many animals species return to raise their families and prepare them for a life that continues to transform and evolve due to climate change and the other forces of nature like earthquakes, wildfires, floods and the influences of mankind.

It may appear that some animal species are well established and very set in their ways, however they are evolving each day to maximize new opportunities provided by an ever-changing planet and the relationships between their habitats and their ability to get what they need to survive. We humans may not notice these changes right away as they can be quite subtle and appear meaningless to us. An example of this is the recent addition of crows and hummingbirds to the Yukon. They are expanding their summer ranges north as the climate warms and they can find enough nectar producing flowers to sustain them as they explore new habitats in the north. The flowering plants they depend on are also moving further north and their presence here will result in other changes that may take us some time to see and understand as they move into habitats presently occupied by the traditional species we normally focus on. Change is all around us, but it can be difficult to see clearly or understand the scope of these changes.

So take the time to look beyond the megafauna and other species we consider to be normal, you may see something astounding. Just ask Whitehorse bird enthusiast Cameron Eckert who found and photographed an adult female Calliope Hummingbird, on Herschel Island in June of 2017, 1,800 km north of its traditional breeding range.

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.

Explore by Category

Explore by Author