Wolves of Isle Royale (1966) Wolves vs Moose

The single

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

-single

prey Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

relationship between

wolves The wolf (''Canis lupus''; plural, : wolves), also known as the gray wolf or grey wolf, is a large Canis, canine native to Eurasia and North America. More than thirty subspecies of Canis lupus, subspecies of ''Canis lupus'' have been reco ...

and

moose The moose (in North America) or elk (in Eurasia) (''Alces alces'') is a member of the New World deer subfamily and is the only species in the genus ''Alces''. It is the largest and heaviest extant species in the deer family. Most adult mal ...

Isle Royale Isle Royale National Park is an American national park consisting of Isle Royale – known as Minong to the native Ojibwe – along with more than 400 small adjacent islands and the surrounding waters of Lake Superior, in the state of Michigan ...

Lake Superior Lake Superior in central North America is the largest freshwater lake in the world by surface areaThe Caspian Sea is the largest lake, but is saline, not freshwater. and the third-largest by volume, holding 10% of the world's surface fresh wa ...

is unique, and has been the subject of detailed study for over 50 years. Isle Royale, the principal island of

Isle Royale National Park Isle Royale National Park is an American national park consisting of Isle Royale – known as Minong to the native Ojibwe – along with more than 400 small adjacent islands and the surrounding waters of Lake Superior, in the state of Michigan ...

Michigan Michigan () is a state in the Great Lakes region of the upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the 10th-largest state by population, the 11th-largest by area, and the ...

in the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

, is an isolated island with little

migration Migration, migratory, or migrate may refer to: Human migration * Human migration, physical movement by humans from one region to another ** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...

of animals into and out of the island, and as a

national park A national park is a nature park, natural park in use for conservation (ethic), conservation purposes, created and protected by national governments. Often it is a reserve of natural, semi-natural, or developed land that a sovereign state dec ...

, human interaction and impact on the two species is also limited. Both the wolves and the moose first became established populations on Isle Royale in the 1900s. Over the fifty years of the study, the populations of both moose and wolves have shown repeated spikes and declines and have not settled to a balanced relationship. The moose populations have ranged from 500 to 2500 while the number of wolves has ranged from almost 50 to down to two.Just 2 wolves left on Isle Royale, Detroit News, Retrieved April 18, 2016: http://www.detroitnews.com/story/news/local/michigan/2016/04/11/isle-royale-wolves-two/82893406/ From 2018 to 2019, 19 wolves were released at Isle Royale in hopes of bringing stability to the ecosystem, and as of 2020, there are estimated to be 14 wolves remaining on the island. The relationship between wolves and moose on Isle Royale has been the subject of the longest predator-prey research study, begun in 1958."Overview of the Ecology and Research of Wolves and Moose on Isle Royale." The Wolves and Moose of Isle Royale. April 16, 200

The wolves have been subject to inbreeding and carry a spinal deformity.''Isle Royale pack down to 2 female wolves'' by John Myers March 30, 2011 ''Duluth News Tribune'' newspaper As of the 2014 count, there were only 9 wolves on the island, with the 2015–2017 counts showing only 2. A review completed in 2014 determined that new wolves would not be introduced into the park to attempt a genetic rescue, but as of December 2016, the National Park Service had instead decided to introduce 20 to 30 wolves to the island. In 2018, three females and one male wolf from Minnesota were transferred to the island system. Isle Royale National Park is made up of about 400 islands, and is in the northwest portion of

. It is about from Michigan's shore, and from the Canadian shore. The main island is about long, and wide at the widest point, with an area of . There are no roads, and no motorized vehicles are allowed on the island. The park is closed from September to May during which the wolf-moose study personnel are the only human residents on the island.

Wolf-moose dynamics interactions

As an isolated island, Isle Royale initially had neither wolves nor moose. The moose are believed to have either swum across

from

Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...

in the early 1900s or were stocked on the island by man for the purpose of recreational hunting.Flesher, John. "Biologist Never Tires of Watching Wolves, Moose on Isle Royale.
The Boston Globe
March 24, 2006. April 9, 2006 In 1949 a few wolves, possibly only a single pair, crossed an ice bridge from

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...

to the island during a harsh winter.Line, Les. "In Long-Running Wolf-Moose Drama, Wolves Recover From Disaster." The New York Times March 19, 1996. April 3, 200

/ref> But because only one pair of wolves migrated to the island, they have suffered from severe

inbreeding Inbreeding is the production of offspring from the mating or breeding of individuals or organisms that are closely related genetically. By analogy, the term is used in human reproduction, but more commonly refers to the genetic disorders and o ...

. According to Rolf Peterson, a professor at

Michigan Technological University Michigan Technological University (Michigan Tech, MTU, or simply Tech) is a public research university in Houghton, Michigan, founded in 1885 as the Michigan Mining School, the first post-secondary institution in the Upper Peninsula of Michigan. ...

and the lead wolf-moose researcher, "Moose were isolated here 100 years ago. Most of the

gene In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...

s are still here, but they have enough population (to compensate). There are so few wolves that they have lost genetic variability. The scientific dogma suggests that they are not going to make it."Weier, Anita. "Isle is Perfect Laboratory for Moose and Wolves – Their Interactions Studied Since 1958. (Saturday Extra)" The Capital Times (Madison, WI) (May 31, 2003): 1B. In fact, all of the wolves' DNA on Isle Royale can be traced back to one ancestor. Inbreeding leads to inbreeding depression and fitness problems, often accompanied by violent social rejection by other wolves. When the study began in 1958, many researchers believed the two species would eventually reach a population equilibrium of about 25 wolves and 1,500 moose; but there has been no sign of this, with populations fluctuating unpredictably.Myers, John. "Isle Royale's Moose Numbers Continue Crash.
Duluth News Tribune
March 10, 2006. April 2, 2006 The highest number of moose observed since the arrival of wolves was 2,450 in 1995. The highest number of wolves observed was 50 in 1980 followed by a population crash to 14 by 1982. As of 2005, there were 540 moose, the lowest recorded, and a relatively high population of 30 wolves. In 2008, there were 700 moose and 23 wolves. The density of the two species depends strongly on the density of

forage Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock. Historically, the term ''forage'' has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used m ...

. Moose prefer

birch A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech-oak family Fagaceae. The genus ''Betula'' contains 30 ...

and

aspen Aspen is a common name for certain tree species; some, but not all, are classified by botanists in the section ''Populus'', of the ''Populus'' genus. Species These species are called aspens: *'' Populus adenopoda'' – Chinese aspen (China ...

trees, which used to grow plentifully on the island, but over a century of moose browsing have been largely replaced by the less nutritious

balsam fir ''Abies balsamea'' or balsam fir is a North American fir, native to most of eastern and central Canada (Newfoundland west to central Alberta) and the northeastern United States (Minnesota east to Maine, and south in the Appalachian Mountains to ...

, which now makes up 59% of a moose's diet.McLaren, B.E., and R.O. Peterson. "Wolves, moose, and tree rings on Isle Royale. (Isle Royale National Park, Michigan)." Science 266.n5190 (Dec 2, 1994): 1555(4). Even this has declined dramatically: as of 2002,

understory In forestry and ecology, understory (American English), or understorey (Commonwealth English), also known as underbrush or undergrowth, includes plant life growing beneath the forest canopy without penetrating it to any great extent, but abov ...

growth of balsam fir was at 5%, down 40% from 19th century observations. The plant is more plentiful on the east side of the island, which draws a higher concentration of moose. Because balsam fir does not give sufficient moisture, moose have recently been spotted eating snow, a very rare occurrence. They have also been sighted eating

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. When the moose population grows too high, the balsam fir population crashes, leading to a crash in the moose population, in a continuing population "see-saw". Moose mostly die from the consequences of

malnutrition Malnutrition occurs when an organism gets too few or too many nutrients, resulting in health problems. Specifically, it is "a deficiency, excess, or imbalance of energy, protein and other nutrients" which adversely affects the body's tissues a ...

: they become emaciated and slowed down by

arthritis Arthritis is a term often used to mean any disorder that affects joints. Symptoms generally include joint pain and stiffness. Other symptoms may include redness, warmth, swelling, and decreased range of motion of the affected joints. In som ...

, until they are easy prey for a

wolf pack A pack is a social group of conspecific canines. Packs aren't formed by all canines, especially small sized canines like the Red fox. The number of members in a pack and their social behavior varies from species to species. Social structure is v ...

. Also, calves suffer from malnutrition when they are born during a winter with snow too deep for easy foraging. Moose make up nine-tenths of an Isle Royale wolf's diet (the remainder being

snowshoe hare The snowshoe hare (''Lepus americanus''), also called the varying hare or snowshoe rabbit, is a species of hare found in North America. It has the name "snowshoe" because of the large size of its hind feet. The animal's feet prevent it from sink ...

and

beaver Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers ar ...

). Moose in their prime years commonly outrun wolves in a hunt, especially on soft snow: moose can cross snow two feet deep at . Even if wolves can catch up to a moose, they cannot always bring it down; researchers often find wolves with hunting bruises and scars. To improve their chances, wolves pick out moose which are calves, old, diseased, or injured. The typical moose killed is about 12 years old and suffers from arthritis, osteoporosis, and/or periodontitis."Isle Royale is a study in moose and wolves." Akron Beacon Journal (Akron, OH) (Dec 29, 2005): NA. Eighty to ninety percent of moose are brought down by wolves rather than directly by disease,Peterson, R.O., R.E. Page, and K.M. Dodge. "Wolves, moose, and the allometry of population cycles." Science 224 (June 22, 1984): 1350(3) and each wolf kills an average of between 0.44 and 1.69 moose per month.Vucetich, JA & RO Peterson. 2004. Long-term population and predation dynamics of wolves on Isle Royale. Pages 281–292 in Biology and Conservation of Wild Canids, edited by D. Macdonald & C. Sillero-Zubiri, Oxford University Press.

Wolf population dynamics

Wolves on the island have, historically, been separated into three or four packs, with each pack usually having between three and eight members, including two or three pups. The number of wolves in a pack depends mainly on the amount of snow that fell in the previous winter. In winters with light snow, pups tend to leave the pack to find mates, so packs run at four or five members; in heavily snowy winters, the pups stay with the pack, which can reach ten to twelve members. If many members of a pack die, the pack dissolves and a new one forms within a year. One pack will dissolve about once every thirty years. In 2006, the wolf population, with the exception of 10 loners and separate pairs, formed three packs; the ''east pack'', the ''middle pack'', and the ''Chippewa Harbor pack''."Moose population decline leaves Isle Royale wolves scrapping for food." The America's Intelligence Wire (March 11, 2006): NA. Wolf packs on the island have been known to fight to try to extend their

territory A territory is an area of land, sea, or space, particularly belonging or connected to a country, person, or animal. In international politics, a territory is usually either the total area from which a state may extract power resources or a ...

and, thus, supply of moose. In 2006, the east pack killed Chippewa Harbor pack's alpha male, as witnessed by John Vucetich, a professor at

and one of the lead researchers on the island, who believed that the Chippewa Harbor pack may die off without their leader.

Old Gray Guy

During the winter of 1997 a particularly virile wolf (later named "Old Gray Guy" and wolf No. 93) crossed the 15 miles of ice to Isle Royale. Old Gray Guy was larger and more territorial than the other Isle Royale wolves. His own pack grew to an unusually large 10 wolves, and displaced and drove to extinction one of the other 4 packs. He was so-named because as he aged his fur became very pale, an unusual phenomenon. It was determined that by 2009, 56% of the wolves on Isle Royale had descended from Old Gray Guy. "We don't know of any other instance — except when they first came — of wolves crossing the ice," said John A. Vucetich, the lead author of a study of the wolves published online in The Proceedings of the Royal Society B in 2011. "The entire population is descended from a single female." The wolf population on Isle Royale is small, averaging only about 23 wolves. By the end of his eight years of breeding, he produced 34 pups, those had produced an additional 45 pups. Such a genetic impact is evidence for substantially greater fitness of Old Gray compared to the other inbred wolves on the island. Scientists expected that such an introduction would create a "genetic rescue" population boom, but it did not happen. "A co-author of the study, Rolf O. Peterson, a research professor at Michigan Technological University, said that the population of Isle Royale hangs on by a thread, as it has for decades. The average reproduction after the Old Gray Guy arrived was no different from before. Yet this does not mean that he had no effect." "The simple interpretation is that genetic rescue doesn't work," said Vucetich, an assistant professor of wildlife ecology at Michigan Technological University. "But what happened here is that when the immigrant came in 1997, in the decade that followed, the moose population declined radically. It's plausible that we didn't see an effect because the wolves were suffering from some other trouble that disguised the benefit. What if wolf No. 93 had never arrived? Vucetich said that it is impossible to know for sure, but the Isle Royale wolves might have disappeared completely. It may be that the Old Gray Guy arrived just in time."Nicholas Bakalar, New York Times April 4, 2011 https://www.nytimes.com/2011/04/05/science/05wolf.html?_r=1 Wolf Crosses the Lake Superior Ice to Become Leader of the Pack"

Trends

Initially, it was thought that the wolf and moose populations would reach a stable balance. However, during the nearly sixty years of the study, the populations of both species have fluctuated up and down with the number of moose ranging from a high of nearly 2500 down to 500 and the number of wolves ranging from a high of 50 down to one in 2017/18. During 2016, the wolf population was nearly extirpated with only two severely inbred wolves present. The moose population was about 2/3rd of its historical maximum with ample forage and growing rapidly. Absent a new infusion of migrant wolves, or human intervention, the original situation of a high moose population limited only by starvation is the prospect. However, in December 2016, the

National Park Service The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational propertie ...

(NPS) put forward a plan in which they would add 20 to 30

to the island in order to prevent the pack from disappearing completely. In December 2017, Sarah Hoy et al. of Michigan Technological University published results of a 40-year study showing a decrease in the size and lifespans of moose. Analysis of moose skulls documents a 16% shrinkage likely consistent with warming winters which are correlated with smaller brain size in one-year-old moose. The moose population has tripled in the past decade, reaching about 1,600 in the 2017 survey, but as wolf die off approaches, competition for food due to overpopulation will become a further stress on moose. In March 2018, with the release of the final Environmental Impact Statement, the NPS formally proposed to relocate 20 to 30 wolves to the island over a three-year time period, starting immediately. An official Record of Decision was released on 7 June 2018 selecting this preferred alternative over several others including taking no action, introducing wolves over a longer 20-year period, and delaying immediate action but allowing for the possibility of future action after the continued monitoring of moose population metrics. As of June 2018, the NPS is actively developing specific implementation strategies. By the end of 2018, three females and a male were trapped in Minnesota and relocated to the park, with more to come. Over the following months the newly introduced male wolf died and one of the females left the island via an ice bridge. In early 2019 eleven more wolves were trapped in Canada and released in the park. Three of the fifteen wolves on the island appeared to be forming a new pack in late 2019. As many as 14 wolves were on the island as of April 2020. At least two new pups were noticed in September 2020.

Other species

Once a moose is brought down and killed, wolves have to compete with

scavenging Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding be ...

raven A raven is any of several larger-bodied bird species of the genus ''Corvus''. These species do not form a single taxonomic group within the genus. There is no consistent distinction between "crows" and "ravens", common names which are assigned t ...

s. Ravens are tenacious scavengers that can easily dodge the strike of a wolf and are unbothered by them. Ravens can eat and store up to in a few days, which is minuscule compared to the storage capacity of wolves, which is up to in just a few hours. Other anti-social species have an effect, though rather small, on the relationship between wolves and moose on Isle Royale. Before wolves hunted them to

extinction Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

coyote The coyote (''Canis latrans'') is a species of canis, canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecologica ...

s used to inhabit the island. Beavers and snowshoe hares also have an effect on both populations, because beavers and snowshoe hares are the only two animals that wolves prey on excluding moose, constituting a tenth of an Isle Royale wolf's diet. The beaver population has sharply declined since the arrival of wolves, but they still are present, and though they are not a prime food source for typical wolves, they are the second to moose as the most consumed animal by the wolves on the island."Species of Lesser Significance.
ParkNet
July 4, 2002. National Park Service. May 18, 2006 Beavers benefit both species. They are as easy prey for wolves and they create aquatic macrophytes, very nutritional plants for moose, although the macrophytes are also consumed by the beavers. Though wolves are thought to contribute to the decline in beaver, researchers believe that the decline of aspen, the primary food source of beavers, which used to be plentiful, could have led to their decrease. Beavers have been exposed to predation by having to travel long distances to find only parts of the island where aspen remains. Snowshoe hares, the third most consumed animal by wolves on Isle Royale constitute a very small portion of the wolves' diet, because snowshoe hares are so difficult to catch. Researchers have found that wolves do not show much interest in preying on hares, and only feed on them incidentally. Snowshoe hares have a negative effect on moose as they eat some of the same vegetation that moose eat, which only contributes to the decline in appropriate forage for moose. The red fox is yet another animal that inhabits Isle Royale; red foxes mainly feed on snowshoe hares and occasionally scavenge on moose, or any other meat a wolf leaves behind. Wolves do not commonly hunt foxes, though wolves have been observed killing foxes when they attempt to feed on an animal carcass.

Climate effects

Climate Climate is the long-term weather pattern in an area, typically averaged over 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorologic ...

plays a major role in the moose-wolf relationship as well. Since

El Niño El Niño (; ; ) is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (approximately between the International Date L ...

hit in 1998, the climate has warmed up, which has significantly affected the moose population across North America."Predators and prey affected by warming. (Ecology)(decline in numbers of North American moose, increase in number of wolves)(Brief Article)." USA Today (Magazine) 133.2711 (August 2004): 7(1). The warmer climate in recent years has produced more Moose winter ticks, which consume the blood of animals, making them more susceptible to

anemia Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, th ...

, and induce the moose to scratch off their hair, exposing them to

hypothermia Hypothermia is defined as a body core temperature below in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe h ...

in cold weather. A moose can have tens of thousands of ticks feeding on its blood at one time, each sucking up to one milliliter of blood. The biting ticks cause a lot of discomfort for the moose, so they try to get the ticks off their bodies by biting off their hair, and rubbing up against trees. This preoccupies moose, and keeps them from browsing for food, which can lead to malnutrition. Compounded with blood loss, moose weakened by ticks are easier for wolves to kill.Goodrich, Marcia. "Isle Royale Wolf-Moose Study Report.
Michigan Tech News/Media
March 4, 2004. Michigan Technological University. April 3, 2006 Ticks are more prominent in years where spring arrives earlier than usual, because when they fall on ground not covered in snow, then they can reproduce. Otherwise, they die out.Roach, John. "Wolves, Ticks, Send Michigan Moose Numbers Plummeting.

June 6, 2005. April 5, 2006 Then, if the summer is hot, ticks are able to reproduce at a higher rate. Hot summers also lead to moose resting in the shade, or in the water to keep cool, making them easier prey for wolves. Also, hot summers lead to tougher foraging for moose which makes them less prepared and more vulnerable to the winter. Not only has the recent warming of Isle Royale hurt the moose, but completely opposite problems harm them also. Harsh winters pose significant problems to moose, because moose have problems finding food when there is too much snow on the ground. The less snow there is, the more freely moose can move around the island. When there is a significant amount of snow, moose stay in

conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...

swamp A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...

s, making them easier prey for wolves, because they are more confined, and immobilized due to the snow. Deep or heavy snow decreases the speed and agility of moose that is necessary to evade wolf attacks, and calves born during a winter with particularly deep snow are more vulnerable to being weaker prey for wolves later on in their lives because of foraging problems that occur when the snow is deep. The keen survival instincts of moose have been clearly evident from the studying of their actions on Isle Royale. Female moose (called "cows") have been spotted on nearby smaller islands, around the main island of Isle Royale, because they swim across to give birth. This allows for them to give birth and raise their young without the threat of wolves preying on their young when they are vulnerable. This also causes trouble for moose that are born in the winter, because they can no longer swim across the water to another island, and must raise the new calf in the snow. Once the calves are physically mature, they are able to swim back, and are then able to better protect themselves from wolves, as they are then in their prime years.

Studies

In 1958, as a graduate student at Purdue University,

L. David Mech Lucyan David Mech (; born January 18, 1937), also known as Dave Mech, is an American biologist specializing in the study of wolves. He is a senior research scientist for the U.S. Geological Survey and an adjunct professor at the University of Min ...

began studying the wolves of Isle Royale.''The Far Reach: The lifework of a Minnesota biologist circles the world'' by Greg Breining Pages 32-41 Minnesota Department of Resources Conservation Volunteer Magazine. January–February 2004 One of the first publications on the subject of the wolves on the Island of Isle Royale was the book "The Wolves of Isle Royale" by Mech which led to the prominence of both the author and the topic. The book was published in 1966 by the Department of the Interior, having evolved from his doctoral thesis. Mech's project would become the world's longest-running predator-prey study.''A Reasonable Illusion'' by Conor Mihell ''Sierra'' magazine November/December 2019 issue Pages 30-35

References

External links

The Wolves and Moose of Isle Royale

Isle Royale National Park Web site

Bibliography

*"Food Fight: Wolves Pack Up to Out-Eat Ravens." Ascribe Higher Education News Service (August 19, 2004): NA.
''The Moose of Isle Royale,''
(1934).

Adolph Murie Adolph Murie (September 6, 1899 – August 16, 1974), the first scientist to study wolves in their natural habitat, was a naturalist, author, and wildlife biologist who pioneered field research on wolves, bears, and other mammals and birds in Arc ...

. Ann Arbor: University of Michigan, Museum of Zoology, Misc. Publication No. 25. Study of the moose population before the wolves arrived. {{DEFAULTSORT:Wolves And Moose On Isle Royale Isle Royale Fauna of the Great Lakes region (North America) Ecological experiments

Moose