Why were All the Yellowstone Wolves Exterminated?

Wolves have a fascinating history about their extermination and reintroduction in the Yellowstone National Park. But the most common question arises, why were all the Yellowstone wolves exterminated? Here, I will provide you short and brief gen of these events in Yellowstone related to wolves.

History of wolves in Yellowstone

At the time of the creation of the Yellowstone National Park, gray wolves’ population was already deteriorated in North America especially, Wyoming, Montana, and Idaho. Despite the declined community, wolves extirpated from the lands of Yellowstone. But why were all the Yellowstone wolves exterminated? Here is the answer.

During the late 1800s, Yellowstone inhabited by farmers and ranchers. Gray wolves of the Yellowstone found their cattle the best source of food, which was unbearable for farmers and ranchers. Hence, they came up with the solution of hunting down and assassinating these wolves.

This extermination was not just a practice of the ranchers, professional enterprises, supported by federal agencies, were also snuffing out gray wolves of the Yellowstone. Moreover, government predator control programs played an essential role in eliminating wolves from the Yellowstone.

Wolves are wily and vicious animals and are feared by human beings and other prey of this species. Hence, they were eradicated from the nearby forests as well. For about seventy years, there were no wolves in the Greater Yellowstone Ecosystem (GYE) and the proximate forests and lands.

Park’s ecosystem without wolves

By 1926, wolves were extinct from the Yellowstone National Park, which had drastic impacts on the ecosystem. This ecological change eliminated top predators from the food chain resulting in a trophic cascade, i.e. the removal of predators changes the prey population and causes dire influences on ecosystem nutrient cycling.

To cut it clear, the removal of wolves eventually increased the elk population, which in turn, devastated the ecosystem by eating young trees and plants in bulk. It resulted in the curtailment of the hosts of trees and plants, like birds and beavers. After this disruption in the ecological system of Yellowstone, Yellowstone National Park lost its glory, and its lands turned into a barren wilderness.


The ecosystem had to be maintained to restore the former glory of Yellowstone. For this purpose, the federal authorities had to reintroduce wolves in the Yellowstone National Park. In recent years, they released three small packs of wolves at various sites in the Northern areas of Yellowstone. The wolf population is now feeding on elk to bring down the vast elk population and to bring the food chain back in line. National Geographic

Recent research has declared the restoration of wolves in the Yellowstone as a success for reinstating the splendor of the magnificent Yellowstone National Park.

The restoration of wolves in the Yellowstone National Park has been a matter of great importance for the last two decades. But many still ask, why were all the Yellowstone wolves exterminated? The retort to this interrogation is quite exciting and I am sure it must have fascinated you as well.


Number of Wolves in Yellowstone

Number of Packs






















Be careful of wild animals.



Wolves can harm humans but they usually stay away. If they come near they are usually looking for food so keep a clean campsite.

Protect yourself with a whistle, throwing rocks, fire, or bear spray. Do not run as they will chase you. Stay back, do not try to pet or feed these wild animals because they may react with a bite. They normally are not a threat to humans and prefer to avoid, so just keep back.

Wolves (Canis lupus) are a fantastic animal, inhabiting the widest distribution of any land mammal, capable of thriving in multiple climates and preying on a wide variety of other mammals. A geographic range so broad, testifies to the wolves adaptability and high tolerance for a variety of environmental conditions. Wolves can survive sweltering heat (120F) and subzero temperatures (-70). Capable of traveling 45 miles a day and reaching speeds of about 35mph to capture prey in forest, prairies, deserts, swamps, tundra, and mountains.

This flexibility continues to food consumption, where wolves are able to gorge on prey, but also able to fast during lean months. Despite this plasticity, wolves lives are difficult and often fall prey to accidents or predators or illness. If not stricken down by nature, they can live up to 13 years in the wild. The incredible plasticity of wolf’s ecological habitats will continue to be seen as more facts are uncovered. Humans paradoxically present the greatest reduction in wild wolf ranges, due to persecution while also continually increasing populations of domesticated dogs.


Wolves have a very strong bite to crush bones from their prey, with the gray wolf having the strongest bite. The bite is very powerful and the power generally ranges at 400 pounds per square inch. When attacking, they can reach up to a power of 1200 pounds per square inch. They have 42 teeth.

Wolf bite compared to other animals’ bite and humans

Wolves’ bite is very powerful and they have the strongest bite among canids, i.e., dog family. The German shepherd, which is among the dogs with the most powerful bites, has a biting power of about 750 pounds per square inch which is about half of an attacking wolf.

Large cats such as Jaguar and Siberian Tiger are also as powerful as the wolf and they reach up to 700 and 950 pounds per square inch, respectively.

Animals with a higher biting power than this include Gorillas, American Alligators and crocodiles with a biting power of up to 1500, 2125 and 5000 pounds per square inch, respectively.

The biting power of humans is quite low compared to that of the wolf since it’s just 300 pounds per square inch.


Basic Canid Characteristics

Wild canids inhabit every continent with Antarctica being the exception. Their body sizes range from about 10 inches seen in the fennec fox to the beautiful gray wolf which can reach 5 feet long. Their basic form is essentially universal among the canids, making identification easy. The bush dog, raccoon dog, and some domesticated dogs do fall outside those typical body forms. Canids have long legs and agile slim bodies. The muzzle is elongated compared to the feline family. Their zygomatic arches (cheekbone) are wide and they have characteristically smooth and bulbous auditory bullae. Their tails are long and bushy and their fur changes with the season.

Canids have 5 toes (the African wild dog is the only exception) with their thumb being reduced in size and not touching the ground. In domesticated dogs this fifth toe is further reduced into what is known as a dewclaw, a vestigial artifact. Male canids create a copulatory die during mating, using the bulbus glandis at the base of their penis. This locks the male and female together for a period of up to an hour.

Wolf Characteristics

Wolves have broader snouts and shorter ears and longer tails then their jackal and coyote relatives. They have decently long legs used for chasing prey and navigating through snow drifts during winter months. Compared to their other near relatives, their teeth are large and heavy, often crushing bone. Wolves molars have flat chewing surfaces, less so than a coyote, because they eat less vegetation. European wolves are typically the largest with average weights around 85 pounds. North American wolves follow at around 80 pounds, and Indian and Arabian wolves are the smallest at around 55 pounds.

Wolves have incredibly dense winter fur with a short undercoat and coarse guard hairs. Guard hairs are the outermost layer, that are seen to protrude from the softer fur. Much of their dark pigmentation is found in the guard hairs, giving the appearance of a rest along the neck and spine of wolves (and other canines). Their fur is capable of keeping them comfortable in open areas at temperatures as low as -40F. Wolves will place their muzzles between their legs and cover their faces with their tails as means to conserve heat. Heat regulation of the foot pads is independent of the rest of the body, only being maintained just above tissue-freezing to conserve energy, since these pads contact ice and snow constantly. FAQ –

Wolf fur color is highly variable, depending on species and latitude. Eurasian wolf coats typically contain yellow, orange, red, and brown colors with black dominating the tips of their guard hairs. North American species have significant coat range. Those living close to the arctic are white, and moving further south into Mexico they become predominantly grey. The Rocky Mountains and British Columbia contain wolves that have predominantly black coats.

Canid Dentition

Carnivores developed a specialized dentition pattern that is seen in bears, leopards, dogs, raccoons, and other carnivores. They have carnassials which are modified molars that are paired together, upper and lower, to allow for improved shearing. Modern carnivores carnassial teeth are made of the fourth upper premolar and the first lower molar (P4/m1). The size and shape of these teeth do vary among carnivores, depending on dietary differences. Bears have more blunted carnassials due to their omnivorous diet. Hypercarnivorous canids like wolves will have sharper carnassials. These teeth are vital to carnivore survival, and injury or wearking of these teeth in the wild can lead to death by starvation for that animal.

Basic Habitat and Life Cycle

Historically wolves were widely distributed across Eurasia and North America. Human activities, including fear, have led to a reduction in their range, especially in western Europe, the United States, and Mexico. As previously mentioned, wolves are found in essentially all habitats, forests, wetlands, grasslands, tundra, pastures, deserts, and mountains. The biggest deterrents for healthy wolf populations are human presence and lack of prey.

Wolves predominantly hunt in packs, this helps protect them during the harsh winters in their northern ranges. Although wolves can survive on their own if necessary. They feed on herbivorous hoofed animals, and a pack can take down a 1,500 pound herbivore. Wolves are capable of identifying weak, injured, or old animals even among packs of herbivores. These intelligent choices increase prey capture chance and reduce energy expenditure per chase.

In North America wolves prey on elk, caribou, white-tailed deer, mule deer, and moose. Eurasian wolves prey on moose, red deer, roe deer, and even wild board. Wolves will supplement their diet with smaller animals including rodents, hares, waterfowl, even lizards, and snakes. European wolves are known to eat fruit including pears and apples and berries, and North American wolves often eat wild blueberries and raspberries. Unfortunately human encroachment often forces wolf populations to resort to livestock and even garbage, further increasing tensions between humans and wolves.

Wolves fare well against interactions with other canids, often killing coyotes and foxes, during disputes over prey. Wolves don’t fare as well against bears. Brown bears will typically win disputes over carcasses, even against entire wolf packs.. In other locales, the existence of their tight-knit packs again proves useful against other predators such tigers and hyenas.

Within packs there is further social structure. Wolves form mated pairs and bond with their offspring. Lone wolves rarely stay alone for long, typically they are in search of a mate to form their own pack. Packs are usually 5 to 8 individuals, but there can be very large packs. Up to 42 wolves have been observed in a single pack. Loss of pack members is highly stressful for the remaining wolves. Offspring will stay with their original pack for one to four years before moving on.

These packs establish large territories and will often kill lone wolves ranging within their territory, especially if that animal is capable of competing for breeding rights. Wolf packs continually travel, an average of 16/mi per day around their territory in search of passing prey. They mark their territories as other animals do, using urine, feces, or anal gland scents. Wolves will avoid the fringes of their territories, due to lethal confrontations with other packs. Studies have shown these confrontations may be a principal cause among wolf deaths, up to 65%.

Wolves are monogamous, usually remaining with their mated pair for the rest of their life. Although if a mate dies, another is usually quickly secured. Females can produce a litter every year, and this is typical. Dens are constructed during the summer when prey is plentiful, usually in natural coverings like cliffs, holes, or rock fissures. Females usually give birth to 4-5 young initially and as they age, this can increase to up to 14 young per litter. Sadly their mortality rate is very high, between 60-80%. Female wolves tend to their litter for the first month, and then the pups begin to start leaving the den for short periods as they gain the agility to flee from dangerous situations.

Early Mammals to Early Canids

Megafauna mammals are typically over 100 pounds. Wolves are on the cusp of being considered megafauna, weighing 65-180 pounds for males and 50-120 pounds for females. While this term is often associated with the large land mammals of the last ice age, many still exist today. The earliest mammals were tiny, coexisting with the dinosaurs back before the massive extinction event at the end of the Cretaceous, 65 million years ago. Up to half of all species went extinct when an asteroid struck the Earth, including all dinosaurs except for early birds.

The fossil record indicates that mammals may have had limited population disruptions from this event. Removal of top level predators allowed for mammals to thrive and disperse into further niches. As small mammals moved into these vacant niches, their body sizes exploded. Most modern mammals can trace their evolutionary history back to mammals between the size of mice and dogs.

About 10-15 million years after this extinction event (50-52 million years ago) some mammals had evolved from Cretaceous era insectivores, into a group called Miacids. These mammals lived during the Paleocene and Eocene, were small fox-sized animals, and still have living ancestors today in Africa. Physically they looked like civets and were carnivores. They likely fed on lizards, birds, and smaller mammals. Another 10-15 million years of evolution and around 40-37 million years ago, the first true carnivores diverge from the Miacids.

Interestingly these earliest carnivores split into two clades, due to differing composition of the middle ear of the skull and surrounding bones. These two clades were the feliformia, or cat-like carnivores and the caniforms, the dog-like carnivores. The official timing of this split is contested, many insisting closer to the first divergence from Miacids and others say millions of years later in the Miocene. The first Canidae, appeared in the fossil record in North America around 37-33 million years ago and didn’t radiate into Eurasia until the Miocene (23 million years ago) and South America until only 5 million years ago.

Cynodictis was an early small elongated canid, similar and size to a fox. It is believed to have lived in trees and been somewhat arboreal. For years it was seen as an early ‘canid’, but recently it’s been found to likely be a close relative of the extinct Amphicyons, also known as bear dogs. Prohesperocyon wilsoni was uncovered in Texas in the early 1990’s. Dating to 36 million years ago, it was decisively identified as an early true Canidae at the base of Canid evolution, due to loss of the upper third molar which provided shearing bite power and an enlarged bony bulla.


The 7 million year period between 37- 30 million years ago, marked large separations and speciation within the canid family. The subfamily Hespercyoninae diverged first and later went extinct in the Miocene, as did the Borophaginae. The Caninae subfamily is the only of the three to continue onto modern day, including wolves, foxes, jackals, domesticated dogs, and coyotes. These extinctions are likely attributed to body mass increases combined with specialized hypercarnivorous diets. This meant Hespercyoninae and Borophaginae species needed significant caloric needs and we’re unable to survive times of low food availability.

Caninae Radiation

Entering the Miocene the Canidae family was left with the Caninae subfamily. Radiation away from southerwestern North America occurred around 10 million years ago, including the Canis, Urocyon, and Vulpes genera. The Eucyon genus were the first canines to enter Asia using the land bridge connecting Alaska to Russia. This radiation is attributed to continued development of their specialized lower carnassials, which were specialized for chewing and shearing flesh.

The Pliocene saw the spread of an early coyote-like canine, throughout North America, called Canis lepophagus. There is some disagreement over descendants of this species, but most researchers recognize the cranial morphology is slightly too different from wolves and coyotes to be closely related, but that it may be a common ancestor of both. During this epoch, the Isthmus of Panama formed allowed canids to successfully radiate into South America. The resulting diversifications include the extinct dire wolf (Canis dirus) and the gray fox (Urocyon cinereoargentus). Other unique South American species resulting from this new range and an abundance of new niches include the maned wolf, short-eared dog, bush dog, and more.


Wolf Line Appears

Currently the oldest definitely identified wolf species is Canis. priscolatrans, emerging during the Late Pliocene and early Pleistocene in North America. There is some disagreement about this being a true species, as cranial morphology falls within the ranges of another more endemic species of North America, Canis edwardii, first dating to 2.3 million years ago and going extinct around 300,000 years ago. C. edwardii forms a small clade with C. latrans (coyotes) and C. aureus (golden jackal), but the first is appeared earliest in the fossil record indicating it is likely the ancestry of the coyote and golden jackal. Canis ambrusteri emerged around 0.8 million years ago, becoming endemic across North and Central America before evolving into the dire wolf (Canis dirus) and spreading into South America.

In Europe, Canis etruscus appeared around 1.9 million years ago. This species led to C. mosbachensis (commonly known as the Mosbach wolf) which is widely considered the immediate ancestor of the modern gray wolf. The dating of the Mosbach wolf places it between C. etruscus seen in China and Europe in the Early Pleistocene and the modern grey wolf. This wolf was smaller than the wolves of today, as wolves have overall grown larger with evolution. C. mosbachensis is hypothesized to have diverged, with one population moving into North America early and becoming C. rufus (red wolf) while the rest remained in Europe and Asia and evolved further into C. Lupus.

The first grey wolf (Canis Lupis), seems to have evolved within Europe and Asia around 300,000 years ago before spreading into North America using the Bering land bridge. The fossil record indicates there were likely 3 separate movements into North America, with four extant C. lupus lineages found using MtDNA studies. Initially the dire wolf and gray wolf coexisted until the dire wolf when extinct. This extinction is attributed to a large herbivorous extincion around 11,500 years ago upon which the scavenger dire wolves relied upon.


Domesticated Dogs

Domestication is a process in which humans control the reproduction of an animal or plant to select for desirable traits. Humans have used domestication for thousands of years. The very first animal domesticated was the grey wolf roughly 15,000 years ago. The specifics have been lost in a complicated gene flow and re-mixing with wild grey wolves. Scientists now believe there were multiple domestications and potentially simultaneous domestications of dogs in two different locations, Europe and Asia.

As grey wolves we’re already excellent hunters, humans likely attempted to select for friendly less-aggressive traits. During the glacial period, scientists believe it was mutually beneficial for humans and wolves to coexist closely. Following the domestication of the wolf into dogs (Canis familiaris), humans then used this towards cultivation and domestication of other animals such as sheep, goats, pigs, and later animals like horses and donkeys.




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