You may have heard that one thing in an ecosystem can affect every other thing in that ecosystem. In Yellowstone we are watching the ripple effect caused by the return of the gray wolf. Wolves were exterminated by the 1930s and absent from the park for decades until reintroduced in 1995.
Now that wolves are back, researchers are discovering how they affect other species in the park. Though the coyote population increased during the wolves’ absence, wolves are now reducing the number of coyotes in areas of the park where they compete for prey. Pronghorns could benefit since coyotes prey heavily on pronghorn fawns. Fewer coyotes could lead to an increase in fox because those two animals compete for smaller prey species like rodents.
Since elk are the most common prey of wolves in Yellowstone, their numbers are coming down from an all-time high reached while wolves were gone. Because wolves kill the weakest animals, they make elk herds healthier by removing the old, young and infirm. Elk may change their movements, distribution, and foraging behavior now that wolves are back.
Changes in elk browsing patterns could lead to increased growth in aspen and willow communities, which could affect other animals and birds like the yellow warbler and willow flycatcher. There is already an increase in beaver colonies in the Northern Range of the park where the wolf population density is highest.
When wolves kill prey to eat, many scavengers take part in the feast. Grizzly bears, coyotes, ravens, magpies, eagles and numerous insects all eat from wolf-killed carcasses. Grizzly bears repeatedly steal carcasses from some wolf packs in the park. With bears getting food from wolves, will they have more cubs or shorten their hibernation? Will they find less winter-killed carcasses to eat when they emerge from their winter dens since wolves have already taken the weakest prey animals over the winter? Will bears learn to follow wolf packs and let wolves do the hunting for them?
The effect wolves have on so many plants and animals is teaching us more about them and their role in the complex web of this ecosystem. There’s still much to learn. Though wolves are only one piece to the vibrant puzzle that is Yellowstone, it’s exciting to witness the comeback of a threatened species as wolves reclaim their place here.
Two canine species in Yellowstone are coyotes and wolves. These carnivores may look similar, but since they compete for prey, they can be arch enemies.
In fact, wolves are notorious for running coyotes away from their kills and sometimes attack and kill coyotes in their territory. Wolves typically hunt larger prey than coyotes do and can take down animals as large as bison and moose. But their prey of preference in Yellowstone is elk. Coyotes like to eat large prey too but can survive on small prey like mice and voles if necessary.
Both coyotes and wolves typically live in packs in the park. And they both have thick fur, especially in winter.
Though there is a vast difference in the size of a coyote and a wolf, coyotes are sometimes mistaken for gray wolves. Gray wolves can actually be black, white or gray. If you see a white or black canine, it’s a wolf. But the grey ones can be more difficult to identify. A rusty hue (or tan/brown?) is more typical of a coyote around here.
The biggest difference is size. A wolf is three times larger than a coyote and can weigh from 80 to 130 pounds. Usually our coyotes are much less than 40 pounds. A wolf stands 3 feet high and often people are surprised at how big they are if they see one at a close range. When an animal is far away from you, however, its size can be hard to determine.
Look for the other differences in appearance. Coyotes have a pointier snout and ears compared to the blockier, more rounded head of a wolf. Coyotes sport more dainty feet and ankles. They leave a 2 ½ inch footprint while a wolf leaves a 4 ½ inch track—closer to the size of an adult human hand.
Although wolves have longer legs than coyotes and stand much taller, they have a stockier, more solid appearance since coyotes’ legs are much thinner toward their feet. Coyotes almost look dainty in comparison.
The howl of the wolf is distinctly different from that of coyotes as well. Wolves have a low, deep mournful-sounding howl compared to the coyote’s higher pitched howl that is usually infused with lots of yipping.
If you are fortunate enough to spot one of these canines in the park, try to correctly identify it by its size, appearance, or howl. See if you can make any comparisons between the wild ‘dogs’ of Yellowstone and their domesticated cousins you may have at home.
Yellowstone is home to two species of bears. Visitors are sometimes rewarded with sightings of black bears or grizzly bears in the wild.
Though it is dangerous and unlawful to feed bears this used to be a common practice in the past. In fact bears often waited along the roadsides for handouts from passing motorists and entered campgrounds in search of food. Bears fed nightly at open garbage dumps in the park while visitors watched. The close proximity of humans and bears was dangerous for both species. Many park visitors were injured by bears or suffered property damage and many bears were killed or removed from the park.
Eventually the park decided that human foods should not be available to bears. Now we have special bear-proof garbage cans and visitors are very good about keeping a clean camp and not allowing bears to get human foods. The number of injuries and incidents of property damage due to bears has plummeted and bears are safer now as well.
While it’s true bears no longer line up along the roadsides or congregate at open garbage dumps, many people still see them from their cars. It’s all the more exciting to glimpse bears in their natural habitat foraging for food and interacting with their young. In 2006, bears caused over 700 traffic jams while visitors got to peek at bears in the wild being bears and doing what they do naturally.
If you would like to see a bear, think like a bear. Grizzlies often forage in open meadows while black bears prefer to stick to the trees or the edges of forests where there is more cover. During the summer months, bears often nap during the heat of the day and are more active at dawn and dusk.
Think about what foods they’re searching for: in the spring it might be winter-killed animals, newly born elk calves, and flowers. They may be fishing for spawning trout or rooting for grubs and insects, roots, tubers and other vegetation or small mammals. Berries and whitebark pinenuts are tasty treats in the fall as are army cutworm moths in the high elevation talus slopes.
They are amazing to watch. Just remember that Yellowstone’s bears are wild and you should never surprise or approach them. Keep at least 100 yards from bears at all times and do not disturb their natural behaviors—they have a lot of eating to do in the summer and fall to be healthy enough to have cubs and be able to sleep all winter long.
Bighorn Sheep can be seen on some of the cliffs in the park. Their remarkable adaptations allow them to escape predators by running down cliffs that the predators cannot handle. Duration: 2 minute 17 seconds
One of the most sure-footed animals in Yellowstone is the big horn sheep. They’re known for the massive curled horns on either side of the ram’s head. But don’t expect all of them to sport large coiled horns. Only the rams or adult males have full curls, while ewes and lambs have much shorter spikes.
The horns are made of keratin (like hair and fingernails) and form over a small extension of bone from the skull. The outer ends of horns are hollow and if the tips break or splinter they won’t grow back. The horns grow from the base getting larger and curling more each year.
Annual growth rings in the horns can help you determine the age of the sheep. As a ram gets older his horns may curve in a spiral all the way back around beside his eyes. He may have to scrape them against something to wear them down so he doesn’t lose peripheral vision.
Rams use their horns to gain dominance within a herd and access to females. The rut is in November when rams may challenge each other by running at each other and then rising on their hind legs just before they butt heads and ram their horns.
These stout males can weigh about 300 lbs with 20 to 40 pounds in their horns. Eventually one ram runs away or acts subordinate and the challenge ends. These jousts for dominance mean the larger, stronger males get to mate.
Ewes have one or two lambs in May or June and the lambs climb almost as well as their mothers within a day or so of birth.
Big horn sheep have concave feet which allow them to run and leap around on steep and rocky slopes. There they’re safe from most predators and can forage with little competition for forbs and grasses. They browse more shrubby plants in the winter and their underhair of angora keeps them well-insulated in wind and snow.
Perhaps their tendency to rely on vision more than their sense of smell or hearing led to a reduction in big horn sheep numbers in the early 1980s. The population is still slowly recovering from a pinkeye epidemic that wiped out 60% of the population.
Count yourself lucky if you see big horn sheep in Yellowstone as there are only about 250 in the park and they inhabit rugged, high, rocky terrain. Your best chances at spotting them are along the slopes of Mt. Washburn where some migrate in the summer, and in the Gardner River Canyon and Mt. Everts, across the Yellowstone River from Calcite Springs, and above Soda Butte.
Look closely since their tan fur blends in well with the rocky cliffs. Don’t feed them even if they venture down to the roadways. This makes them more prone to getting hit by cars. Keep them wild, healthy and majestic.
One of the best wildlife watching experiences in Yellowston, and there are many, is getting to glimpse river otters. Though people rarely see them, they are definitely around.
Otters have a sleek cylindrical body and a long thick pointed tail. They weigh from 10 to 30 pounds and are about 4 feet long with a third of that in their tails. They have webbed feet, short claws and short, dark brown, very dense fur. They can swim for 2-3 minutes underwater, closing their ears and nostrils and using their whiskers to help them locate prey.
They eat fish, crayfish, frogs, and sometimes young muskrats. They usually catch the slowest-swimming fish and then surface to eat them, often on a log. And they don’t always like to share. They can be feisty when it comes to competing with others for food.
They mate in March and April and have 2-4 pups in a litter each year. Offspring usually stick with their mother for a year until she has the next litter. Females don’t dig their own dens but use dens dug by other animals or existing natural shelters. Mothers teach their young to swim and help them develop foraging skills by catching and releasing prey for them.
Sometimes I wonder if I like them so much because otters are like me. They’re curious and nearsighted. They eat fish and like to swim. Or maybe we enjoy watching otters and wish we were more like them. They’re intelligent and have good memories.
I think what intrigues us most about them is how playful they seem. Their urge to play is strong and they’ll play alone, with each other, and even with other animals. It’s fun to watch them dive and chase, and slide, roll and bound around. Whether they are gliding easily through the water or sliding on chutes of snow and ice, they seem to be having fun.
If you’re interested in seeing otters in Yellowstone, remember they’re going to be near water. They’re mostly active at dawn and dusk, but can be seen any time of day. Otters are easier to spot in winter when their dark fur contrasts with the snow. Since the tip of the tail often drags the ground, they leave a neat track in snow. Look for their tracks and latrine sites or stop in at one of the visitor centers and ask a ranger if anyone has reported a recent sighting.
Their work usually happens in the dead of night. But, if you look across Yellowstone’s landscape their presence is hard to miss. Beavers, with their dam building, have the ability to change an area’s environment like no other creature besides maybe humans.
Meadows become ponds; streams that were once lined with mature trees have only stumps to remind us of the past. The effects of these changes have far reaching consequences. The habitat that is created can have benefits for flora and fauna at every level of the wilderness. New wetlands promote the growth of willows, aspens, cottonwoods and water lilies. These new food sources attract, insects, birds and large mammals like the moose.
Beavers are North America’s largest rodent and they can weigh anywhere from 30 to 60 lbs. They live in colonies with 6-13 family members per lodge. Their flat tail is used to pack mud around lodges and dams. They also can be heard slapping their tail on the waters surface when they feel threatened. Today, Yellowstone is home to approximately 500 beavers and 85 lodges. Those numbers indicate a substantial increase in recent years. There is much debate among researchers as to the cause of the increase.
Some believe that the serge in the beaver population can be tied to wolf reintroduction. Wolves were gone from Yellowstone for 70 years. In their absence, elk could forage in one area for longer periods. Many shoots of plants like willow would be eaten before they established and became a viable food source for beaver. With the return of wolves, elk move more frequently and utilize food sources that are not in the open. This small change in elk behavior enables the willow and other brush as well as young tree seedlings to reestablish along streams.
Others believe that climate change is the major factor in the serge of both beaver and willow. With warmer summers, plants have a few more weeks to mature each season. The longer season may allow plants to produce chemicals that make them unpalatable to elk. While more research could give us some answers, more than likely it is the combination of these changes that have led to an increase in the beaver population.
The best beaver habitats today seem to be in the upper Yellowstone River south of Yellowstone Lake, the Bechler region in the southwest corner of the park, and along the Madison and Gallatin Rivers on the west side. Along the main park roads you are most likely to see beavers south of Mammoth in the Gardner River drainage and in Hayden Valley. Be sure to dress properly, even on the best of days the weather can change here in a hurry.
By trying to understand how population dynamics change in a species like beaver we realize how fragile the ecosystem is. In nature, everything affects everything.
In Yellowstone we can see what wild animals do in their natural habitats. It’s fun to watch them eating, resting, interacting with each other and even raising their young.
What makes the animals so intriguing to us is also what makes them dangerous—their wildness. Though the animals don’t typically stalk or prey on humans, they are WILD. They have been known to charge and attack people who get too close. People have been bitten, gored or injured in the past when they have disturbed park wildlife.
Don’t let this happen to you. Never approach any park wildlife closer than 25 yards. For bears make it no closer than 100 yards to be safe and within the law. Never feed wildlife or allow them access to garbage. You could get bitten, and it often makes an animal lose its natural fear of humans, which endangers both humans and the animal.
Wildlife that have been fed frequently look for handouts around roadways and parking lots where they could be hit by cars. They often approach people and become aggressive. People have been bitten and some wildlife may carry diseases.
The WILD in our wildlife isn’t the only important thing about them—equally important is the LIFE in the wildlife. Don’t let your actions cause the death of park animals. Drive no faster than the speed limit and be especially cautious driving at night, dawn and dusk. Tragically, about 120 large animals are killed each year by vehicles on park roads. Avoid such accidents to keep the wildlife alive and you and your car safe.
When taking photographs remember that the animals need to save their energy to eat, rest, mate and raise young. Be sensitive to not disturb them. If you make an animal change its behavior, that’s considered disturbing it.
It is rare that humans and wild animals can be in such close proximity. Yellowstone is home to amazing creatures. As you visit them in their home, show respect. Keep your distance. Don’t jeopardize your safety or the safety of park animals. Let’s keep it WILD for their sake and ours.
Uinta ground squirrels are sometimes mistaken for prairie dogs. They hibernate for most of the year, coming above ground in the spring and early summer to feed on lush vegetation. Duration: 2 minute 13 seconds
Yellowstone’s winter can seem like it lasts forever. But as the days begin to get longer, a few signs that spring is on its way start to appear. Bears are seen around the geyser basins and the brilliant blue of the mountain blue bird flashes against the remaining snow pack. But of all the tell-tale signs, it is the emergence of Uinta ground squirrels that signals the new season is here.
Young and old visitors alike, spend countless hours entranced by the non-stop activity of Yellowstone’s most abundant small mammal. Uinta ground squirrels, race back and forth, fight and flip each other, only to come to a sudden stop, and raise-up on their hind legs for a better view.
Uinta squirrels seem to do everything in a hurry. Mating season begins as soon as hibernation ends in March or April. After a 28 day gestation, the babies are born. Young females have liters of 4 or 5, while older females have liters of 7 or 8.
When they are 24 days old, baby squirrels emerge from their dens and join the colony on the near endless pursuit of food. There is not much help from the adults after this.
Grasses, forbs, seeds, as well as insects and some carrion make up the majority of the Uinta ground squirrel’s diet. It is not uncommon to see them near roads and trails eating dead members of their own species.
Constant chirping alarms the colony of approaching predators.
Humans are the Uinta ground squirrel’s biggest danger. For some reason, we feel the need to feed wild animals. The food we give them doesn’t store as well as their natural foods and is often inedible by winter. Please, never feed wildlife. It’s not only bad for their health, but it’s also illegal.
By mid-July, it seems the summer is just getting going for humans, but for this squirrel, the year is about over. Just as quickly as they appeared in March, Uinta ground squirrels are gone. The next 8 months are spent hibernating and waiting, waiting to let us know that spring is back.
Our knowledge of mountain lions in Yellowstone is really just being developed. The first study of lion ecology in the park began in 1987. In the early days of Yellowstone, as with most of the west, mountain lions were subject to predator control policies.
Researchers estimate that up to 24 mountain lions live here and that number is increasing. There are now four collared mountain lions in Yellowstone.
Female lions weigh around 100 lbs and have a life span of 14 years, while the 160 lb males only live about 10 years. By the time they are 1 ½ years old, most males move as far as 400 miles from where they were born. The females disperse around 150 miles.
Cats are very territorial. Males, or toms, have home ranges of 150 square miles that overlap with several females. Other toms could be killed if they are caught trespassing into a larger males range.
Mountain lions can mate at any time of year, but in Yellowstone, most mate in winter or early spring. After a 92 day gestation, 2 or 3 one pound kittens are born in dens.
Elk and mule deer are the main sources of food for mountain lions. After a kill, carcasses are buried or cached. It takes nearly 4 days to consume one of those large ungulates. On average, lions go 9 ½ days between kills.
Confrontations with mountain lions are rare in Yellowstone. If you do encounter one, get your group to stay together and carry any small children. It is best to act dominant. Stare directly are the cat, and show your teeth.
For me, one of the best things about wilderness areas is that physically we are not the top of the food chain. We must see better, hear better, and smell better. Yellowstone’s wilderness is dangerous, but the rewards are priceless.
Since 1872, 322 bird species have been sighted in Yellowstone. Many of those species are seen as they migrate with the seasons. It is believed that 148 species nest in the park. Of all those species, there is none more important to the future health of Yellowstone than the Clark’s Nutcracker.
While these birds can be found in a variety of habitats, they are most often associated with sub-alpine conifer forest. You may hear Clark’s Nutcrackers before you see them. Watch for small flocks working their way from tree to tree as they search for food. It is this search for their favorite food, pine seeds, that makes this bird so important for the ecosystem.
Clark’s Nutcrackers have the ability to hold several dozen pine seeds in their throat at a time. They bury those seeds in caches and return to eat them at a later date. Even through deep snow, they seem to remember where they buried their caches.
Yellowstone is home to two different 5 needle pine species that are used by the Clark’s Nutcrackers. Limber pines are found at lower elevations in the park and whitebark pines are found at higher elevations.
The caches that are not eaten by the nutcrackers can germinate and become new stands of trees. This can help Yellowstone’s whitebark pine forest battle climate change. As average temperatures rise, the upper treeline can adjust to higher elevations.
Clark’s Nutcrackers are also important to grizzly bears. Grizzly bears love pine seeds but are not good tree climbers. Grizzlies search the treeline for pine seed caches and when they find them they can be rewarded with hundreds of seeds that are high in fat.
So when you just thought you were watching birds, you were really watching a forest engineer. Planting trees, battling climate change, and feeding bears, that’s the Clark’s Nutcracker.
Moose are one of those animals that visitors love to see. In the early days of Yellowstone, it was rare to see a moose. Today, they can be hard to find, but if you work at it, it is possible.
They’re not as romantic as wolves or bears, but they seem to excite us when we get a chance to watch one browse through the marshy areas around the park. So, how do you find a moose? Start at a visitor center. Ask the rangers if they have heard of any sightings lately. Dawn and dusk seem to be the best times of day, so get out early.
Moose love wetlands and lakes. In the wetlands, they browse on leaves and twigs of willow, gooseberry and buffaloberry bushes. On lakes, moose take advantage of the aquatic plants like water lilies, duckweed or burweed. Moose are excellent swimmers.
Moose mate in the fall. With an eight month gestation, the cows give birth to two or three calves in May or June. The calves must grow fast to survive living in Yellowstone’s harsh environment.
In winter, moose will often move up into mature fir forests. Moose move from tree to tree browsing on needles and twigs. They eat as much as 26 lbs of food a day in summer, half that in winter.
An adult moose can be 6 to 7 feet at the shoulders. Males weigh as much as 1000 lbs; females as much as 900 lbs. Both sexes have a “bell” or dewlap, a furry piece of skin that hangs below their chin. Their bell seems to have no purpose.
With wolves being reintroduced and natural processes like fire being self regulating, the population has decreased. Today’s researchers believe that Yellowstone is home to around 500 moose.
Moose are one of the most dangerous animals in the park. They scare me more than bears do. They may appear gangly and clumsy but they’re ornery and fast. Use every precaution when in moose habitat.
When asked about trumpeter swans, James J. Audubon once said, “You must observe them when they’re not aware of your proximity.” His advice still rings true today.
Trumpeter swans are extremely skittish, especially during nesting periods. Be cautious when viewing swans and never approach nesting swans.
Trumpeter swans are the largest waterfowl native to North America. The all white adults can have a wingspan as great as 8 feet and weigh nearly 30 lbs.
In the 1930’s it was believed that less than 100 trumpeters remained in the wild. Habitat loss, market hunting, and their reclusive nature all contributed to the population decline. Red Rocks National Wildlife Refuge in Montana, just west of Yellowstone, was formed in 1935 to protect the trumpeter swan.
Trumpeters build their nests with pond vegetation like cattail or bulrush. Nests can be 5 feet wide and weigh hundreds of pounds. Predators and flooding are the biggest dangers for nesting swans.
Trumpeter swans often mate for life. Starting in June, the female, or pen, will lay one cream colored egg every day or two until she has 4 to 6 eggs. It takes just over one month for the eggs to hatch. The young swans, called cygnets, are gray for the first year. Cygnets fledge, or fly for the first time, in September.
As many as 350 swans call the greater Yellowstone region home. In 2006, 14 adult trumpeter swans lived in the park.
Overall, trumpeter swans are rare in Yellowstone. Winter remains the best time to see them here. Swans that summer north of here return to this area in the winter. I hope that on your next trip to Yellowstone you get to experience the beauty, strength and grace of these magnificent birds.