The gray wolf has interbred extensively with the eastern wolf producing a hybrid population termed Great Lakes boreal wolves. Views Read View source View history. This page was last edited on 13 September , at Transdermal patches adhesive patches placed on the skin may also be used to deliver a steady dose through the skin and into the bloodstream. Regulation of the secretion of GnRH, FSH, and LH occurs partially by the negative feedback of testosterone and estradiol at the level of the hypothalamo-pituitary.
A review determined that some, but not all, randomized controlled studies have found that AAS use correlates with hypomania and increased aggressiveness, but pointed out that attempts to determine whether AAS use triggers violent behavior have failed, primarily because of high rates of non-participation. Compared with individuals that did not use steroids, young adult males that used AAS reported greater involvement in violent behaviors even after controlling for the effects of key demographic variables, previous violent behavior, and polydrug use.
The drug response was highly variable. The mechanism of these variable reactions could not be explained by demographic, psychological, laboratory, or physiological measures. A study of two pairs of identical twins, in which one twin used AAS and the other did not, found that in both cases the steroid-using twin exhibited high levels of aggressiveness, hostility, anxiety, and paranoid ideation not found in the "control" twin.
The relationship between AAS use and depression is inconclusive. There have been anecdotal reports of depression and suicide in teenage steroid users,  but little systematic evidence. A review found that AAS may both relieve and cause depression, and that cessation or diminished use of AAS may also result in depression, but called for additional studies due to disparate data. Androgens such as testosterone , androstenedione and dihydrotestosterone are required for the development of organs in the male reproductive system , including the seminal vesicles , epididymis , vas deferens , penis and prostate.
The pharmacodynamics of AAS are unlike peptide hormones. However, as fat-soluble hormones, AAS are membrane-permeable and influence the nucleus of cells by direct action. The pharmacodynamic action of AAS begin when the exogenous hormone penetrates the membrane of the target cell and binds to an androgen receptor AR located in the cytoplasm of that cell.
From there, the compound hormone-receptor diffuses into the nucleus, where it either alters the expression of genes  or activates processes that send signals to other parts of the cell. The effect of AAS on muscle mass is caused in at least two ways: It has been hypothesized that this reduction in muscle breakdown may occur through AAS inhibiting the action of other steroid hormones called glucocorticoids that promote the breakdown of muscles.
As their name suggests, AAS have two different, but overlapping, types of effects: Some examples of the anabolic effects of these hormones are increased protein synthesis from amino acids , increased appetite, increased bone remodeling and growth, and stimulation of bone marrow , which increases the production of red blood cells. Through a number of mechanisms AAS stimulate the formation of muscle cells and hence cause an increase in the size of skeletal muscles , leading to increased strength.
The androgenic effects of AAS are numerous. Depending on the length of use, the side effects of the steroid can be irreversible. Processes affected include pubertal growth, sebaceous gland oil production, and sexuality especially in fetal development.
Some examples of virilizing effects are growth of the clitoris in females and the penis in male children the adult penis size does not change due to steroids [ medical citation needed ] , increased vocal cord size, increased libido , suppression of natural sex hormones , and impaired production of sperm. Men may develop an enlargement of breast tissue, known as gynecomastia, testicular atrophy, and a reduced sperm count.
Compounds with a high ratio of androgenic to an anabolic effects are the drug of choice in androgen-replacement therapy e. This disassociation is less marked in humans, where all AAS have significant androgenic effects. A commonly used protocol for determining the androgenic: The VP weight is an indicator of the androgenic effect, while the LA weight is an indicator of the anabolic effect.
Two or more batches of rats are castrated and given no treatment and respectively some AAS of interest. Animal studies also found that fat mass was reduced, but most studies in humans failed to elucidate significant fat mass decrements.
The effects on lean body mass have been shown to be dose-dependent. Both muscle hypertrophy and the formation of new muscle fibers have been observed. The hydration of lean mass remains unaffected by AAS use, although small increments of blood volume cannot be ruled out. The upper region of the body thorax, neck, shoulders, and upper arm seems to be more susceptible for AAS than other body regions because of predominance of ARs in the upper body.
After drug withdrawal, the effects fade away slowly, but may persist for more than 6—12 weeks after cessation of AAS use.
Overall, the exercise where the most significant improvements were observed is the bench press. The measurement of the dissociation between anabolic and androgenic effects among AAS is based largely on a simple although arguably unsophisticated and outdated model involving rat tissue bioassays.
The intracellular metabolism theory explains how and why remarkable dissociation between anabolic and androgenic effects can occur despite the fact that these effects are mediated through the same signaling receptor, and of course why dissociation is invariably incomplete.
An animal study found that two different kinds of androgen response elements could differentially respond to testosterone and DHT upon activation of the AR. Changes in endogenous testosterone levels may also contribute to differences in myotrophic—androgenic ratio between testosterone and synthetic AAS. Testosterone can be metabolized by aromatase into estradiol , and many other AAS can be metabolized into their corresponding estrogenic metabolites as well.
The major effect of estrogenicity is gynecomastia woman-like breasts. AAS are androstane or estrane steroids. As well as others such as 1-dehydrogenation e. The most commonly employed human physiological specimen for detecting AAS usage is urine, although both blood and hair have been investigated for this purpose.
The AAS, whether of endogenous or exogenous origin, are subject to extensive hepatic biotransformation by a variety of enzymatic pathways.
The primary urinary metabolites may be detectable for up to 30 days after the last use, depending on the specific agent, dose and route of administration. A number of the drugs have common metabolic pathways, and their excretion profiles may overlap those of the endogenous steroids, making interpretation of testing results a very significant challenge to the analytical chemist. Methods for detection of the substances or their excretion products in urine specimens usually involve gas chromatography—mass spectrometry or liquid chromatography-mass spectrometry.
The use of gonadal steroids pre-dates their identification and isolation. Medical use of testicle extract began in the late 19th century while its effects on strength were still being studied. In the s, it was already known that the testes contain a more powerful androgen than androstenone , and three groups of scientists, funded by competing pharmaceutical companies in the Netherlands, Germany, and Switzerland, raced to isolate it.
The chemical synthesis of testosterone was achieved in August that year, when Butenandt and G. Wettstein, announced a patent application in a paper "On the Artificial Preparation of the Testicular Hormone Testosterone Androstenoneol.
Clinical trials on humans, involving either oral doses of methyltestosterone or injections of testosterone propionate , began as early as Kennedy was administered steroids both before and during his presidency. The development of muscle-building properties of testosterone was pursued in the s, in the Soviet Union and in Eastern Bloc countries such as East Germany, where steroid programs were used to enhance the performance of Olympic and other amateur weight lifters.
In response to the success of Russian weightlifters, the U. The new steroid was approved for use in the U. It was most commonly administered to burn victims and the elderly.
The drug's off-label users were mostly bodybuilders and weight lifters. Although Ziegler prescribed only small doses to athletes, he soon discovered that those having abused Dianabol suffered from enlarged prostates and atrophied testes.
Three major ideas governed modifications of testosterone into a multitude of AAS: Androgens were discovered in the s and were characterized as having effects described as androgenic i. Although anabolic steroid was originally intended to specifically describe testosterone-derived steroids with a marked dissociation of anabolic and androgenic effect, it is applied today indiscriminately to all steroids with AR agonism-based anabolic effects regardless of their androgenic potency, including even non-synthetic steroids like testosterone itself.
The legal status of AAS varies from country to country: Unlawful distribution or possession with intent to distribute AAS as a first offense is punished by up to ten years in prison. Those guilty of buying or selling AAS in Canada can be imprisoned for up to 18 months.
In Canada, researchers have concluded that steroid use among student athletes is extremely widespread. A study conducted in by the Canadian Centre for Drug-Free Sport found that nearly 83, Canadians between the ages of 11 and 18 use steroids. AAS are readily available without a prescription in some countries such as Mexico and Thailand. The history of the U.
The same act also introduced more stringent controls with higher criminal penalties for offenses involving the illegal distribution of AAS and human growth hormone. By the early s, after AAS were scheduled in the U. In the Controlled Substances Act, AAS are defined to be any drug or hormonal substance chemically and pharmacologically related to testosterone other than estrogens , progestins , and corticosteroids that promote muscle growth.
The act was amended by the Anabolic Steroid Control Act of , which added prohormones to the list of controlled substances , with effect from January 20, In the United Kingdom, AAS are classified as class C drugs for their illegal abuse potential, which puts them in the same class as benzodiazepines. Part 1 drugs are subject to full import and export controls with possession being an offence without an appropriate prescription. There is no restriction on the possession when it is part of a medicinal product.
Part 2 drugs require a Home Office licence for importation and export unless the substance is in the form of a medicinal product and is for self-administration by a person. Many other countries have similar legislation prohibiting AAS in sports including Denmark,  France,  the Netherlands  and Sweden.
United States federal law enforcement officials have expressed concern about AAS use by police officers. It's not that we set out to target cops, but when we're in the middle of an active investigation into steroids, there have been quite a few cases that have led back to police officers," says Lawrence Payne, a spokesman for the United States Drug Enforcement Administration.
Following the murder-suicide of Chris Benoit in , the Oversight and Government Reform Committee investigated steroid usage in the wrestling industry. The documents stated that 75 wrestlers—roughly 40 percent—had tested positive for drug use since , most commonly for steroids. AAS are frequently produced in pharmaceutical laboratories, but, in nations where stricter laws are present, they are also produced in small home-made underground laboratories, usually from raw substances imported from abroad.
As with most significant smuggling operations, organized crime is involved. In the late s, the worldwide trade in illicit AAS increased significantly, and authorities announced record captures on three continents. In , Finnish authorities announced a record seizure of A year later, the DEA seized In the first three months of , Australian customs reported a record seizures of AAS shipments. Illegal AAS are sometimes sold at gyms and competitions, and through the mail, but may also be obtained through pharmacists, veterinarians, and physicians.
AAS, alone and in combination with progestogens , have been studied as potential male hormonal contraceptives. From Wikipedia, the free encyclopedia. This article is about androgens as medications. For androgens as natural hormones, see Androgen. Ergogenic use of anabolic steroids. Use of performance-enhancing drugs in sport. The wolf has a large number of apocrine sweat glands on the face, lips, back, and between the toes.
The odor produced by these glands varies according to the individual wolf's microflora and diet, giving each a distinct "odor fingerprint". A combination of apocrine and eccrine sweat glands on the feet allows the wolf to deposit its scent whilst scratching the ground, which usually occurs after urine marking and defecation during the breeding season. The follicles present on the guard hairs from the wolf's back have clusters of apocrine and sebaceous glands at their bases. As the skin on the back is usually folded, this provides a microclimate for bacterial propagation around the glands.
During piloerection, the guard hairs on the back are raised and the skin folds spread, thus releasing scent. The pre-caudal scent glands may play a role in expressing aggression, as combative wolves raise the base of their tails whilst drooping the tip, thus positioning the scent glands at the highest point. The components of anal sac secretions vary according to season and gender, thus indicating that the secretions provide information related to gender and reproductive state. The secretions of the preputial glands may advertise hormonal condition or social position, as dominant wolves have been observed to stand over subordinates, apparently presenting the genital area for investigation,  which may include genital licking.
During the breeding season, female wolves secrete substances from the vagina , which communicate the females' reproductive state, and can be detected by males from long distances. Urine marking is the best-studied means of olfactory communication in wolves. Its exact function is debated, though most researchers agree that its primary purpose is to establish boundaries.
Wolves urine mark more frequently and vigorously in unfamiliar areas, or areas of intrusion, where the scent of other wolves or canids is present.
So-called raised leg urination RLU is more common in male wolves than in females, and may serve the purpose of maximizing the possibility of detection by conspecifics, as well as reflect the height of the marking wolf. Only dominant wolves typically use RLU, with subordinate males continuing to use the juvenile standing posture throughout adulthood.
The gray wolf is a habitat generalist, and can occur in deserts , grasslands , forests and arctic tundras. Habitat use by gray wolves is strongly correlated with the abundance of prey, snow conditions, absence or low livestock densities, road densities, human presence and topography. The warmth of the footpads is regulated independently of the rest of the body, and is maintained at just above tissue-freezing point where the pads come in contact with ice and snow. During the autumn-spring period, when wolves are more active, they willingly lie out in the open, whatever their location.
Actual dens are usually constructed for pups during the summer period. When building dens, females make use of natural shelters such as fissures in rocks, cliffs overhanging riverbanks and holes thickly covered by vegetation.
Sometimes, the den is the appropriated burrow of smaller animals such as foxes, badgers or marmots. An appropriated den is often widened and partly remade. On rare occasions, female wolves dig burrows themselves, which are usually small and short with 1—3 openings. The odour of urine and rotting food emanating from the denning area often attracts scavenging birds such as magpies and ravens.
As there are few convenient places for burrows, wolf dens are usually occupied by animals of the same family. Though they mostly avoid areas within human sight, wolves have been known to nest near domiciles , paved roads and railways. Although wolves primarily feed on medium to large sized ungulates , they are not fussy eaters.
Smaller sized animals that may supplement the diet of wolves include marmots , hares , badgers , foxes , weasels , ground squirrels , mice , hamsters , voles and other rodents , as well as insectivores. They frequently eat waterfowl and their eggs. When such foods are insufficient, they prey on lizards , snakes , frogs , rarely toads and large insects as available. In times of scarcity, wolves readily eat carrion , visiting cattle burial grounds and slaughter houses.
In Eurasia, many gray wolf populations are forced to subsist largely on livestock and garbage in areas with dense human activity, though wild ungulates such as moose , red deer , roe deer and wild boar are still the most important food sources in Russia and the more mountainous regions of Eastern Europe. Other prey species include reindeer , argali , mouflon , wisent , saiga , ibex , chamois , wild goats , fallow deer and musk deer.
Animals preferred as prey by North American wolves include moose, white-tailed deer , elk , mule deer , bighorn sheep , Dall's sheep , American bison , muskox and caribou.
Wolves supplement their diet with fruit and vegetable matter. They willingly eat the berries of mountain ash , lily of the valley , bilberries , blueberries and cowberry. Other fruits include nightshade , apples and pears. They readily visit melon fields during the summer months. Gray wolves typically dominate other canid species in areas where they both occur. In North America, incidents of gray wolves killing coyotes are common, particularly in winter, when coyotes feed on wolf kills.
Wolves may attack coyote den sites, digging out and killing their pups, though rarely eating them. There are no records of coyotes killing wolves, though coyotes may chase wolves if they outnumber them. Brown bears typically dominate wolf packs in disputes over carcasses, while wolf packs mostly prevail against bears when defending their den sites. Both species kill each other's young. Wolves eat the brown bears they kill, while brown bears seem to only eat young wolves.
The majority of black bear encounters with wolves occur in the species' northern range, with no interactions being recorded in Mexico. Wolves have been recorded on numerous occasions to actively seek out black bears in their dens and kill them without eating them.
Unlike brown bears, black bears frequently lose against wolves in disputes over kills. Wolves may encounter striped hyenas in Israel, Central Asia and India, usually in disputes over carcasses. Striped hyenas feed extensively on wolf-killed carcasses in areas where the two species interact.
One-to-one, hyenas dominate wolves, and may prey on them,  but wolf packs can drive off single or outnumbered hyenas. Large wolf populations limit the numbers of small to medium-sized felines. Wolves encounter cougars along portions of the Rocky Mountains and adjacent mountain ranges.
Wolves and cougars typically avoid encountering each other by hunting on different elevations. In winter, however, when snow accumulation forces their prey into valleys, interactions between the two species become more likely.
Wolves in packs usually dominate cougars and can steal kills. They have been reported killing mothers and their kittens. Wolves may kill lynxes by running them down, or killing them before they can escape into trees.
Leftovers of wolf kills are sometimes scavenged by wolverines. Wolverines usually wait until the wolves are done feeding, but have been known to drive away wolves from kills. However, there have been confirmed reports of wolf packs killing wolverines.
Other than humans, tigers appear to be the only serious predators of wolves. Wolves appear capable of escaping competitive exclusion from tigers only when human persecution decreases tiger numbers. Proven cases of tigers killing wolves are rare and attacks appear to be competitive rather than predatory in nature, with at least four proven records of tigers killing wolves without consuming them. However, deliberate human persecution has reduced the species' range to about one third, because of livestock predation and fear of attacks on humans.
Wolf population declines have been arrested since the s, and have fostered recolonization and reintroduction in parts of its former range, due to legal protection, changes in land-use and rural human population shifts to cities. Competition with humans for livestock and game species, concerns over the danger posed by wolves to people, and habitat fragmentation pose a continued threat to the species.
Despite these threats, because of the gray wolf's relatively widespread range and stable population, it is classified as least concern by the IUCN. Although wolf-dog hybridization in Europe has raised concern among conservation groups fearing for the gray wolf's purity, genetic tests show that introgression of dog genes into European gray wolf populations does not pose a significant threat.
Also, as wolf and dog mating seasons do not fully coincide, the likelihood of wild wolves and dogs mating and producing surviving offspring is small. The extermination of Northern Europe 's wolves first became an organized effort during the Middle Ages , and continued until the late 19th century. In England , wolf persecution was enforced by legislation , and the last wolf was killed in the early sixteenth century during the reign of Henry VII.
Wolves lasted longer in Scotland , where they sheltered in vast tracts of forest, which were subsequently burned down. Wolves managed to survive in the forests of Braemar and Sutherland until The extirpation of wolves in Ireland followed a similar course, with the last wolf believed to have been killed in The Sami extirpated wolves in northern Sweden in organized drives.
By , few wolves remained in Sweden, because of the use of snowmobiles in hunting them, with the last specimen being killed in The gray wolf was exterminated in Denmark in and Norway's last wolf was killed in The species was decimated in 20th century Finland, despite regular dispersals from Russia. The gray wolf was only present in the eastern and northern parts of Finland by , though its numbers increased after World War II. In Central Europe , wolves were dramatically reduced in number during the early nineteenth century, because of organized hunts and reductions in ungulate populations.
In Bavaria , the last wolf was killed in , and had disappeared from the Rhine regions by Today, wolves have returned to the area.
The louveterie was abolished after the French Revolution in , but was re-established in In , up to 1, wolves were killed, with many more by poison. In Eastern Europe , wolves were never fully exterminated, because of the area's contiguity with Asia and its large forested areas.
However, Eastern European wolf populations were reduced to very low numbers by the late nineteenth century. Wolves were extirpated in Slovakia during the first decade of the twentieth century and, by the mid-twentieth century, could only be found in a few forested areas in eastern Poland.
Wolves in the eastern Balkans benefitted from the region's contiguity with the former Soviet Union and large areas of plains, mountains and farmlands. Wolves in Hungary occurred in only half the country around the start of the 20th century, and were largely restricted to the Carpathian Basin.
Wolf populations in Romania remained largely substantial, with an average of 2, wolves being killed annually out of a population of 4, from — An all-time low was reached in , when the population was reduced to 1, animals. The extermination of wolves in Bulgaria was relatively recent, as a previous population of about 1, animals in was reduced to about — in In Greece, the species disappeared from the southern Peloponnese in Despite periods of intense hunting during the eighteenth century, wolves never disappeared in the western Balkans, from Albania to the former Yugoslavia.
In Southern Europe , wolf extermination was not as complete as in Northern Europe, because of greater cultural tolerance of the species. Wolf populations only began declining in the Iberian Peninsula in the early 19th-century, and was reduced by a half of its original size by Wolf bounties were regularly paid in Italy as late as The recovery of European wolf populations began after the s, when traditional pastoral and rural economies declined and thus removed the need to heavily persecute wolves.
By the s, small and isolated wolf populations expanded in the wake of decreased human density in rural areas and the recovery of wild prey populations. The gray wolf has been fully protected in Italy since , and now holds a population of over 1,, By the wolves in the Western Alps imposed a significant burden on traditional sheep and goat husbandry with a loss of over 5, animals in In Spain , the species occurs in Galicia , Leon , and Asturias.
Although hundreds of Iberian wolves are illegally killed annually, the population has expanded south across the river Duero and east to the Asturias and Pyrenees Mountains. In , wolves began recolonising central Sweden after a twelve-year absence, and have since expanded into southern Norway.
As of , the total number of Swedish and Norwegian wolves is estimated to be at least one hundred, including eleven breeding pairs. The gray wolf is fully protected in Sweden and partially controlled in Norway. The Scandinavian wolf populations owe their continued existence to neighbouring Finland's contiguity with the Republic of Karelia , which houses a large population of wolves.
Furthermore, the decline in the moose populations has reduced the wolf's food supply. Wolf populations in Poland have increased to about — individuals since being classified as a game species in Poland plays a fundamental role in providing routes of expansion into neighbouring Central European countries.
In the east, its range overlaps with populations in Lithuania, Belarus , Ukraine , and Slovakia. A population in western Poland expanded into eastern Germany and in the first pups were born on German territory.
A few Slovakian wolves disperse into the Czech Republic, where they are afforded full protection. Wolves in Slovakia, Ukraine and Croatia may disperse into Hungary, where the lack of cover hinders the buildup of an autonomous population.
Although wolves have special status in Hungary, they may be hunted with a year-round permit if they cause problems. Romania has a large population of wolves, numbering 2, animals. The wolf has been a protected animal in Romania since , although the law is not enforced. The number of wolves in Albania and Macedonia is largely unknown, despite the importance the two countries have in linking wolf populations from Greece to those of Bosnia and Herzegovina and Croatia.
Although protected, sometimes wolves are still illegally killed in Greece, and their future is uncertain. Wolf numbers have declined in Bosnia and Herzegovina since , while the species is fully protected in neighbouring Croatia and Slovenia. During the 19th century, gray wolves were widespread in many parts of the Holy Land east and west of the Jordan River. However, they decreased considerably in number between and , largely because of persecution by farmers.
Soviet wolf populations reached a low around , disappearing over much of European Russia. The population increased again by to about 75,, with 32, being killed in By the s, wolf extermination remained a priority in the NWP and Awadh. Overall, over , wolves were killed for bounties in British India between and The wolf was deemed a threat to ranching, which the Meiji government promoted at the time, and targeted via a bounty system and a direct chemical extermination campaign inspired by the similar contemporary American campaign.
The last Japanese wolf was a male killed on January 23, near Washikaguchi now called Higashi Yoshiro. Japanese wolves likely underwent a process of island dwarfism 7,—13, years ago in response to these climatological and ecological pressures. There is little reliable data on the status of wolves in the Middle East , save for those in Israel and Saudi Arabia , though their numbers appear to be stable, and are likely to remain so.
Israel's conservation policies and effective law enforcement maintain a moderately sized wolf population, which radiates into neighbouring countries, while Saudi Arabia has vast tracts of desert, where about — wolves live undisturbed. The mountains of Turkey have served as a refuge for the few wolves remaining in Syria.
A small wolf population occurs in the Golan Heights , and is well protected by the military activities there. Wolves living in the southern Negev desert are contiguous with populations living in the Egyptian Sinai and Jordan. Throughout the Middle East, the species is only protected in Israel.
Elsewhere, it can be hunted year-round by Bedouins. Little is known of current wolf populations in Iran, which once occurred throughout the country in low densities during the mids. The northern regions of Afghanistan and Pakistan are important strongholds for the wolf. Overall, India supports about , wolves, scattered among several remnant populations. Although protected since , Indian wolves are classed as endangered, with many populations lingering in low numbers or living in areas increasingly used by humans.
Although present in Nepal and Bhutan , there is no information of wolves occurring there. Wolf populations throughout Northern and Central Asia are largely unknown, but are estimated in the hundreds of thousands based on annual harvests. Since the fall of the Soviet Union , continent-wide extermination of wolves has ceased, and wolf populations have increased to about 25,—30, animals throughout the former Soviet Union.
In China and Mongolia , wolves are only protected in reserves. Mongolian populations have been estimated at 10,—30,, while the status of wolves in China is more fragmentary. The north has a declining population of an estimated wolves, while Xinjiang and Tibet hold about 10, and 2, respectively.
It exists in southern China, which refutes claims made by some researchers in the Western world that the wolf had never existed in southern China. It occurred all over the mainland, save for the southeastern United States, California west of the Sierra Nevada , and the tropical and subtropical areas of Mexico. Large continental islands occupied by wolves included Newfoundland , Vancouver Island , southeastern Alaskan islands, and throughout the Arctic Archipelago and Greenland.
In his November 6, letter to the French Minister of the Marine, Louis Denys de La Ronde reported that the island was home to wolves "of a prodigious size", and sent a wolf pelt back to France to substantiate his claim. As the island was cleared for settlement, the gray wolf population may have been extirpated, or relocated to the mainland across the winter ice: The decline of North American wolf populations coincided with increasing human populations and the expansion of agriculture.
By the start of the 20th century, the species had almost disappeared from the eastern USA, excepting some areas of the Appalachians and the northwestern Great Lakes Region. In Canada, the gray wolf was extirpated in New Brunswick and Nova Scotia between and , and in Newfoundland around It vanished from the southern regions of Quebec and Ontario between and The gray wolf's decline in the prairies began with the extermination of the American bison and other ungulates in the s—70s.
From —, the gray wolf was virtually eliminated from the western USA and adjoining parts of Canada, because of intensive predator control programs aimed at eradicating the species.
The gray wolf was exterminated by federal and state governments from all of the USA by , except in Alaska and northern Minnesota. The decline in North American wolf populations was reversed from the s to the early s, particularly in southwestern Canada, because of expanding ungulate populations resulting from improved regulation of big game hunting.
This increase triggered a resumption of wolf control in western and northern Canada. Thousands of wolves were killed from the early s to the early s, mostly by poisoning. This campaign was halted and wolf populations increased again by the mids. The species' modern range in North America is mostly confined to Alaska and Canada, with populations also occurring in northern Minnesota, northern Wisconsin and Michigan 's Upper Peninsula , and small portions of Washington , Idaho , northern Oregon , and Montana.
A functional wolf population should exist in California by according to estimates by state wildlife officials. In addition, the Mexican wolf Canis lupus baileyi was reintroduced to Arizona and New Mexico in Canada is home to about 52,—60, wolves, whose legal status varies according to province and territory.
First Nations residents may hunt wolves without restriction, and some provinces require licenses for residents to hunt wolves while others do not. In Alberta , wolves on private land may be baited and hunted by the landowner without requiring a license, and in some areas, wolf hunting bounty programs exist. In Alaska, the gray wolf population is estimated at 6,—7,, and can be legally harvested during hunting and trapping seasons, with bag limits and other restrictions.
As of , there are wolves in 28 packs in Yellowstone, and wolves in 25 packs in Idaho. Reintroduced Mexican wolves in Arizona and New Mexico are protected under the ESA and, as of late , number 28 individuals in eight packs. Viral diseases carried by wolves include rabies , canine distemper , canine parvovirus , infectious canine hepatitis , papillomatosis , and canine coronavirus.
Infected wolves do not show any fear of humans, with most documented wolf attacks on people being attributed to rabid animals. Although canine distemper is lethal in dogs, it has not been recorded to kill wolves, except in Canada and Alaska. The canine parvovirus, which causes death by dehydration , electrolyte imbalance , and endotoxic shock or sepsis , is largely survivable in wolves, but can be lethal to pups.
Wolves may catch infectious canine hepatitis from dogs, though there are no records of wolves dying from it. Papillomatosis has been recorded only once in wolves, and likely doesn't cause serious illness or death, though it may alter feeding behaviors.
The canine coronavirus has been recorded in Alaskan wolves, with infections being most prevalent in winter months. Bacterial diseases carried by wolves include brucellosis , lyme disease , leptospirosis , tularemia , bovine tuberculosis ,  listeriosis , anthrax and foot and mouth disease. While adult wolves tend not to show any clinical signs, it can severely weaken the pups of infected females. Although lyme disease can debilitate individual wolves, it does not appear to have any significant effect on wolf populations.
Leptospirosis can be contracted through contact with infected prey or urine, and can cause fever , anorexia , vomiting, anemia , hematuria , icterus , and death. Wolves living near farms are more vulnerable to the disease than those living in the wilderness, probably because of prolonged contact with infected domestic animal waste. Top 10 Tips To Improve Posture.
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