There are few cases of the striking return of a species once eradicated, particularly a large mammalian carnivore, like that of the wolf in the cultural landscapes of Northwestern Europe. This article gives an account of that come-back, as well as on-the-ground insight into the settling of the wolf in parts of the modern European landscape and its ecology and the renewed wolf-human relationships that arise.
Return of the ‘Big Bad Wolf’
Wolves with a long history of stigmatization as a diabolic and misleading character still invoke fear in the minds of many people today, disproportionately contributing to its exposure in the media. Other large carnivores in Europe, like the (reintroduced) lynx, hardly receive that scrutiny or limelight.
The return of the wolf in Northwestern Europe became apparent in Germany around the Millennium, starting with the settlement of a few wolves, originating from Poland, in the region of Lausitz in former Eastern Germany. This was also the region where the ‘last wolf’ of Germany was shot after a drive hunt near Hoyerswerda in 1904; known as the Tiger von Sabrodt. This event marked the official extinction of the wolf in Germany and for Northwestern Europe. Elsewhere in this part of Europe wolves were completely eradicated decades earlier. The last wolf of the Netherlands, according to available records, was shot in 1845 near the southern town of Schinveld. Locations where the last wolves of a region were killed, were often triumphantly marked with a memorial stone; in Germany known as a Wolfstein.
The last officially killed wolf marking extinction of the species in Germany in 1904, known as the ‘Tiger von Sabrodt’.
The eradication of the wolf in Europe began centuries earlier, when the sheep economy became important in the early Middle Ages, during which time the wolf also received the stigma of a diabolical creature in league with the devil. This was an outlook from Christianity which was spreading at the time and displacing pagan culture in which the wolf was generally held in high regard. The killing of wolves was also symptomatic of growing human control over nature. Later in history, a combination of war, famine, waste mismanagement, disease epidemics, overhunting, progressive deforestation, superstition (werewolf legends and (fairy)tales placing the wolf in even more bad light), animal trials, dog-wolf hybridization and rabies fuelled the human-wolf conflict, leading to an all-out war against wolves or lupicide. Perhaps no other animal became so prominent in the dark corners of the human mind as the wolf has; one could say archetypically embedded (Lopez 1978; Bernard 1981; Rheinheimer 1995; Pluskowski 2006; Klees et al. 2015).
The Big Bad Wolf reputation arising in the past is not wholly without foundation. There are accounts from police reports and death certificates of wolves having fatally attacked people in Europe from the Renaissance until the 18th Century; notably in France as researched by cultural historian Moriceau (2013). Children, women and elderly people wandering the countryside in poverty or herding livestock were prime victims. Such extraordinary attacks culminated during rabies epidemics which were at their height in the 17th Century, but also non-rabid wolves were apparently involved. The accounts of wolf attacks, whether or not exaggerated, led to the legendary and regional ‘beast’ stories like that of the La bête du Gévaudan in southern France. The heightening conflict between wolves and people must be seen in the context of the Zeitgeist of that time, with much cultural upheaval taking place.
The advent of more effective poison (strychnine), traps and guns in the 16th Century resulted in efficient killing of wolves and this finally led to their complete disappearance from much of Western Europe; a phenomenon exported to North America by the colonists, where wolves were ultimately killed from airplanes and persecuted to extinction in the US in the late 1970s (McIntyre 1995).
In Europe wolf populations persisted in eastern and southern Europe, with important numbers of the Gray wolf (Canis lupus) lingering in the Baltics, former Balkans (with a sizeable population in the Carpathians) and in Mediterranean countries like Italy. Since World War II there have been several accounts of lone wolves moving into Germany from beyond the Iron Curtain, which has presented a formidable barrier for large mammals until its dismantling in the early 1990s. Interviews with former border guards reveal that wolves frequently probed the fence to cross. The very occasional wolves crossing into West Germany were either shot or killed by traffic (Stoepel 2004; Wörner 2014; Hachtel 2018). A relatively unknown but legendary case of a wolf going far west into West Germany after the second wolf war is that of the Würger vom Lichtenmoor (Hachtel 2018). This concerned a lone wandering wolf that had reached the mire area of Lichtenmoor near the town of Nienburg-Weser in Lower Saxony. This wolf, upon killing several sheep in the area, was shot by a hunter in the summer of 1948; with another wolfstein erected to commemorate this event and making headline news at the time. The landscape that this wolf had returned to – a large mire area with heath and forest – matches many of the current habitats that wolves are settling back into.
With the protection of the Gray wolf in the European Union through the Habitats Directive (in force in 1983) and Bern Convention (Trouwborst 2010) wolf populations in the retreat areas were able to increase. Furthermore, the political revolutions in Eastern Europe in the early 1990s already lessened the hunting pressure on wolves. Another key factor enabling wolves to return to former distribution areas in the west is land abandonment in key parts of Europe. Expanses of unmanaged forests and fields present good habitat for wolves, and wolves do prefer areas with least human activity. Moreover, the food base of large ungulates like red and fallow deer and wild boar has increased in these areas. Wild ungulates are also ‘subsidized’ by crop monocultures and the lack of capacity among hunters to effectively curtail growing ungulate populations has given deer and wild boar a lot of scope over the years.
The countryside of Germany and France is literally teeming with wild herbivores, like these fallow deer clustering in wolf country in Germany.
Since the Millenium the Lausitz region on the border with Poland and the Czech Republic has harbored a founding and core population of wolves for Germany. According to telemetry studies by the wolf monitoring institute Lupus in 2013, there was a cluster of 13 wolf pack territories that occupied a total area of 3500 km2; each pack territory with an average size of 300 km2. The Lausitz holds a great lignite (brown coal) mining area that is still being phased out after Die Wende. The opencast mining has considerably changed the landscape, leaving huge water filled pits, mounts and bare sandy plains. These are abandoned and undergoing ecological succession. Large monotonous stands of Scots pine supply the forestry and remaining mining industry. In between the (former) industrial areas, a mosaic of heathlands, streams, fens and untouched deciduous forests reveal the landscape of old. Some of the sizeable heathlands are still used as military practice sites. With plenty of hiding area and easy hunting terrain, the wolves thrive here on a big supply of wild ungulates (roe deer, red deer, fallow deer, mouflon and wild boar). Many of the people in the region are hardly aware of or are indifferent to the presence of wolves. They go about their business as usual and, for instance, use the forests for recreation without fear; although fright for the Big Bad Wolf persists in other quarters. The only conflict that has arisen concerns livestock and game depredation by wolves. This presents ammunition for a small but prominent group of stakeholders campaigning against the wolves or seeking their regulation. The Lausitz became one of the first demonstration areas in Germany for the application of electric fencing and the use of guard dogs against wolf attacks, mostly on sheep (Ansorge et al. 2010).
Wolf habitat in a former lignite mining area in the Lausitz near the town of Lohsa, in former Eastern Germany. An Eldorado for wolves with a high prey base and large forest expanses to hide from humans, who partly regard these areas as no-mans-land because of the despoiled terrain.
Westward expansion of wolves
The further spread of wolves from the initial Lausitz core population or the shifting ‘wolf front’ to other parts of Germany and toward the west taking place in the last 10 years is striking. The west front expansion was heralded since 2011 by lone wolves in Lower Saxony, in the Belgian Ardennes, the Netherlands and in Denmark. These wandering wolves stayed temporarily or lingered widely in an area, without a mate to bond. Some of these wolves originated from the established German population in the east, but also from Poland, Italy and France.
The westward wolf dispersal over the last 10 years has proceeded predominantly along a line in northwestern Germany. This is a region of Pleistocene deposited sandy plains, with large tracts of heathland (including the great Lüneburger Heide), mires and patchy forest and arable land. Much of the lowland landscape features are similar to the Lausitz; with the exception of brown coal mining. Here wolf packs have established within large mire and heathlands, also used as military training sites (Gomille 2016; Bloch & Radinger 2017; Reinhardt et al. 2018).
The new western wolf populations have recently pushed the so-called wolf front further westward. A wolf litter produces on average four cubs, but can be double that in some cases. Since the first reproduction by a wolf (actually a pairing with a German shepherd) in 2000 in the Lausitz, the wolf population increase in Germany has been exponential. The current (2018-2019) population monitoring estimate by the German wolf documentation authority DBBW stands at 73 packs, 30 wolf pairs and 10 territorial lone wolves awaiting a mate. These numbers are quite accurate, as wolf monitoring and the investigation of livestock depredation within a compensation scheme is well organized in Germany, through regional hunting authorities and scientific bodies and with appointed or voluntary Wolfsberater.
New dilemmas from new arrivals
The dynamics of wolf settlement and shifting of the wolf front in terms of ecology and the human-wolf relationship can be illustrated with the arrival of wolves in the region of Diepholz in Lower Saxony. In the Spring of 2014 a young she-wolf was detected by a camera trap and several sightings by the locals. Through DNA collected from scats (recorded as the female with Haplotype HW02), her origin was traced back to a pack near Gartow, around 300 km to the northeast. Furthermore, being an intelligent, opportunistic but yet inexperienced predator, this she-wolf – known as the Göldenstadter Wölfin began to take livestock disproportionally. Sheep farmers were unprepared and the traditional barb wire was no match for the wolf which could easily scale it. The regional newspaper sensationally headlined the arrival of a ‘blood thirsty’ wolf, showing graphic pictures of disemboweled sheep carcasses. It was not long (in 2016) before a young male wolf joined the female, originating from a pack near Ueckermünde; 500 kilometers northeast on the Polish border. The wolf pair roamed widely in the area and predated as a team on livestock.
Until the end of 2017 around 30 sheep and 2 calves were verifiably taken by the Göldenstedter wolfpair, presenting an extraordinary case of livestock predation compared with other wolf regions in Germany. Furthermore, the wolves were occasionally sighted passing near farms and villages and once near a child day-care. Stakeholders from the farming community and concerned citizens voiced their worries and some demanded that the wolves be ‘removed from nature’ as German policy dictates for ‘problem wolves’ according to stringent criteria. In April 2017 a meeting was held in the town hall of Barnstorf, between the community and representatives from the Lower Saxony hunting association, environmental department and the environmental NGO NABU. This was conducted in typical German fashion with beer-laden tables. The discussion was heated, but also constructive, with anti- and pro-wolf arguments going back and forth. It became apparent that little had been undertaken to apply anti-predatory measures with tailored electric fencing and guard dogs, with farmers awaiting financial support from or laying responsibility with the government.
The wolf consultation meeting between the regional community and wolf authorities in the village of Barnstorf in Germany on 25 April 2017, produced a constructive discussion but with the plight to remove the Göldenstedter wolves, seen by many as a threat to livestock.
Igniting the concern to negative sentiment against the Göldenstedter wolves was not only the loss of livestock combined with some of the innate fear of wolves (‘little red riding hood’ syndrome), but also the ongoing case of Kurti, a young male that was believed to have lost its fear of humans having allegedly been fed by the military on a training area. This wolf was ‘removed from nature’ early that year by the authorities, much to the outrage of the pro-wolf movement. Moreover, the deep and tragic memory of an escaped wolf from a zoo killing a seven year old boy on 13 August 1977 near Delmenhorst – not far north from Diepholz – came up. The authorities responded by pointing to available support through the livestock loss compensation scheme and the intention to radio-track the wolves and monitor their predatory movements on livestock; the latter did not occur.
The wolf pair settled in early spring 2017 and produced four cubs (three males and one female) that were born on a small enclosed industrial area and former military site. Shortly after birth the cubs were taken by their mother to a large nearby mire and peat extraction area surrounded by a large buffer zone of arable land, but not far from dispersed villages in the surrounds. The cubs, growing up fast, joined their parents in full functioning hunting pack late in the Autumn. Tracking their activities revealed much of what is already known about wolf (landscape) ecology and behavior in the literature – notably the authoritative well-researched works by Mech (1970) and Mech & Boitani (2004). This intensive on-going research with a lot of field hours produced fascinating insight into the wolves lives, including feeding ecology and hunting modes, terrain use and behavioural aspects of wolves and other animals around them. It is interesting to compare behavior patterns to what is known of wolf ecology in remote wilderness-type areas. As a wolf researcher one becomes fully engaged with the lives being observed, and gains knowledge of the behavior of a wolf pack and its individual members, occasionally with chance encounters.
The author experienced a rare up-close-and-personal encounter with one of the cubs of the Göldenstedter pack in October 2017, standing eye-to-eye for several seconds at close quarters. The young wolf showed surprise at first (showing a typical lowered head posture) but then advanced with curiosity, at which point it had to be scared off with a hush and wave of the hand. It retreated with its tail between legs.
The hunting wolf pack
The newly established wolf pack with parents and immature pups starts to roam widely around the core area in winter (the core is the summer area with resting and rendezvous places). The wolf family or pack is then at full strength. Pack size in our study areas has so far varied from 5 to 10 animals. Core areas of 3 wolf territories studied in the western part of Lower Saxony and in the Netherlands range between 35 km2 – 100 km2 based on tracking (scat finds). But the actual home ranges can be much greater, and can be mapped more accurately with radio-telemetry.
Wolves in northwestern Germany tend to currently settle within large and serene open mire or heathland areas with dense forest fringes, surrounded by large swathes of arable land functioning as buffer between human settlements and cultural wildlands. These landscapes are utilized for agriculture, hunting, mining, military practice and recreation.
Young wolves born in late April to May grow up fast and reach maturity at the end of the following winter, during which time they may break off early from the family pack to disperse in search of their own territory with a mate. Usually the young males depart from early spring onwards, whilst their sisters may stay longer (up to around 2 years) and help the resident wolf pair to raise the next generation of kin. In reaching maturity the young wolves start to make outings on their own and occupy separate places in quiet corners of the core area. The pack gathers for hunts and other social interaction on so-called rendezvous sites; subtly recognizable (a few scattered bones, scats and trampled vegetation) on open patches of heath and grassland on higher ground. Here the wolves howl at dusk to consolidate the pack; the current researchers were able to record the pack howls of mature wolves mixed with the high yelps of cubs at one rendezvous site.
The advantage of the pack is to be able to efficiently capture large ungulates through co-operative hunting. The wolves appear to have a keen sense and memory of where to hunt, and do so alternately in places within and outside the core area where ungulates concentrate and the terrain is optimal for a surprise or drive attack. A kill like a full-grown fallow deer stag is quickly consumed – within five days or so – leaving nothing but a few spread bones and splinters, antlers and hair. Bones are taken and scattered by the wolves and smaller carnivores. The few kills of deer that were found helped to indicate that weak prey animals are highly selected. judging from inferior antlers. On the wolf hunting grounds deer appear to be more anxious and cluster upon approach. Some German game managers complain that their subject is much less visible than before the wolves arrived. On the other hand it is surprising to observe – from camera trapping – that prey animals and other smaller (meso)carnivores like fox, badger and martens co-exist with wolves within the core area; even though the latter make sure to stay out of the way of wolves. Smaller mammalian carnivores, ravens and raptors certainly benefit from the food scraps.
The fox is no longer top dog in the food chain since the arrival of the wolf. However, despite some claims that wolves should regulate their numbers, foxes and other mesocarnivores appear to thrive alongside the wolves. As camera trapping studies show, smaller carnivores are vigilant for their larger counterparts however, and adjust their movements to avoid risky encounters (a phenomenon known as trophic top-down-regulation).
Wandering wolves and their fate
Many wolves perish on roads and railway tracks, presenting 60% of all known mortality causes. The passing of wolves whose lives one gets to know is deeply saddening. For instance, in January 2018 a young male of the Göldenstedter pack was killed by a train, quite close to the core area. His brother was killed on the road on 11 March near Opoeteren in Belgium, after a journey through the Netherlands. It is likely that the young animal encountered in the forest (see photo below) was one of the two. The third brother ventured deeply into the Netherlands, but has disappeared from the radar since then. Their sister remained with their mother during the summer of 2019, who could be often tracked together. The father, according to authorities, had disappeared under suspicious circumstances. However, tracks of a large male wolf were found roaming widely within the core area this summer. Whether another Göldenstedter pack formed in 2019 is still unknown. Elsewhere, on the huge military training site of Meppen another pack has established with 8 cubs recorded by a surveillance camera in June 2019. The previous year the she-wolf littered six cubs; 2 of which were later killed by traffic.
Monitoring wolves on their trails throughout their large territories is time consuming but rewarding. Tracking consistently on the basis of signs (scats, footprints, scrapes, urine scent marking, molted hair and the occasional find of prey remains) reveals most of their movements. The use of camera traps and sound recording devices provides more information on ranging and behavior. This picture is showing a young wolf still occupying a corner of a natal territory on the Dutch-German border in June, but was killed by a car shortly after this recording.
Wandering young wolves surviving the risks of the modern European landscape and finding quiet natural space and abundant ungulate prey are now filling in the gaps of former ‘haunts’. For the reproductive year of 2019 an estimated total of 300 cubs is expected as new recruits.
Early in 2019 the wolf front shifted from Lower Saxony to the large forested Veluwe area in the center of the Netherlands. The coming of wolves to the Netherlands was previously indicated from 2001 onwards by several lone wolves roaming shortly into the Netherlands and then disappearing or being killed on the road. The wolf pair established itself on the northern part of the Veluwe, in a highly game managed forest and heath area with much human recreation in summer; partly excluded from forbidden game reserves. Finally a wolf pair formed, shortly after a female made quarters, and presumably fostered three cubs based on infrequent camera footage information. In a southern part of the Veluwe a lone female has settled since the fall of 2018; still awaiting a male. These wolves have been closely monitored by Dutch wildlife research authorities using DNA-analysis of scats.
Wolf scat (often a dense mass of fine and coarse bone fragments and hair) deposited frequently and widely on long trails within the wolf core area often present the first signs of residential presence; here on the Veluwe in the Netherlands in April 2019. Calcium rich scats may last for more than a year to serve as ‘flags’ with a different message to mates, pack members and rivals.
Rebirth of the human and wolf relationship
Although an adult wolf has the strength to do considerable damage in an attack, the long persecution history has made wolves innately fearful and evasive of humans; and perhaps this has always been the case. Very occasionally – usually young – wolves are inquisitive toward hiking humans or their canine companions. Roaming in wolf territory presents a sense of excitement, but never incites fear in the author, as threatening situations are very unlikely to arise. This has been the experience all over Germany so far, with only very few wolves showing a lack of fear toward people; but no aggression. It remains surprising to see local people recreating in wolf areas without a care in the world– hiking, horse riding, mountain biking or letting the dog out. The unwanted occurrence of hybridization with dogs is also very rare, with only two reported cases in Germany so far.
Wolves often inhabit areas with ongoing human activities, such as this large-scale peat extraction in a large mire area in the region of Diepholz, Germany. At night – but also during the day – the wolves roam this area in stealth using the rows of piled peat briquettes as cover.
Livestock attacks are mainly attributed to dispersing wolves passing through agricultural areas in search of new territory, and they opportunistically take sheep along the way. According to the German statistics, livestock attacks have increased with the growth and subsequent fecundity of the wolf population, but the numbers vary yearly and switch regionally, according to wolf dispersal and settlement dynamics. Sheep loss by wolves can also be weighed in perspective with other more common mortality causes, including killing by dogs and foxes and through theft, accidents and disease. This range of more common sheep impacts is hardly exposed in the news. The intense emotions raised when wolves kill one or simultaneously more sheep (mass killing) and to a much lesser extent other domestic animals (including goats, ponies, alpaca and calves), usually with a bloody scene, is understandable and should be received with sympathy, swift and proper investigation and financial compensation by the authorities, which in practice is not always the case.
Gaining intimate familiarity with wolves in their territory allows an understanding of their predatory behavior. Resident wolves in most cases switch to hunting wild ungulates and other smaller wild prey including hares, rabbits and voles. Livestock then ranks much less on the menu, with the occasional taking of (in particular) unprotected sheep, usually in the winter months when young and more easily captured ungulates are not available and wolves roam wider in the agricultural landscape. Livestock depredation by wolves in the Diepholz region reduced to almost zero since late summer 2017, in large part due to the wolves settling in a core area rich in prey. Depredation prevention – most effective, albeit costly, with electric fencing and guard dogs in and around wolf core areas – applied by some of the sheep holders may also have contributed to less livestock loss. Unprotected calves within the wolf core area were not even attacked, and wolves have been seen walking past them without interest. Another wolf family established in 2018 on a large military training site on the Dutch-German border near Meppen. This family has been solely hunting wild prey so far; as have the wolves that settled on the Veluwe in the Netherlands in 2019.
Settled wolves predominantly hunt and regulate populations of wild ungulates, with a selection of young and weak individuals. Nothing is wasted and without disturbance only scattered hair and a few bones remain as evidence.
A while after wolf settlement in a region, perception of people towards the neighboring wolves eases to a degree; dependent on the behavior of the wolves and the level of incidence of livestock depredation. The retreat of wolves into their core areas with nothing more than the occasional sighting and some public education, including through seminars, tends to sooth the heated wolf perceptions in nearby human communities.
Views on wolves and willingness to co-exist and apply animal friendly preventive measures properly tailored to the situation (Faß 2018), varies between stakeholders. Realizing the advantage of applying predation prevention, progressive livestock holders do their bit to reduce conflict with the wolf. Once wolves have settled, the commotion around them tends to be less frequent in the media. It continues to be ‘fought’ out country-wide between wolf ‘haters’ and ‘lovers’ on social media and in public discussions; often without middle-ground, well-informed or rational argument. Hardline wolf opposition from conservative quarters is stalwart, often with groundless and repeated argument that the wolf is redundant in the modern cultivated landscape, that it presents a danger and disproportionally suppresses game populations; contrary to the present reality.
Despite evidence for a ‘peaceful’ co-existence based on science-based management , a movement of wolf opponents, including high-level politicians, is actively lobbying against the wolf and is pressing for population regulation or ‘wolf free zones’ in the European Union. So far European wildlife protection policy (through the Habitats Directive) is resisting a legal culling of wolves, of which the effects could be counterproductive. Nevertheless, the successful expansion of the wolf does pose the question of whether limits in terms of wolf ecology and human tolerance will be met.
Paul L. Errington’s statement on the wolf in North America, in his 1967 book Of Predation and Life, is still highly relevant today, also for the European wolf situation: “Of all the native biological constituents of a northern wilderness scene, I should say that wolves present the greatest test of human wisdom and good intentions”
Upon the new arrival of wolves, initially with varying rates of livestock depredation, adaptation of livestock management is a priority. It remains difficult to protect livestock against wandering wolves in large corridor areas, but protection using well-placed electric fencing together with several guard dogs (with public instruction) has proven to be highly effective in and around territorial core areas of wolves.
Ecological keystone role and rewilding icon?
Whether wolves as naturally selective top predators have a disproportionate key impact on the ecology of modern landscapes in Northwestern Europe through trophic cascades – exemplified by the ecological cascade effects in Yellowstone National Park (Ripple &Beschta 2003; Terborg & Estes 2010; Smith&Ferguson 2005) – needs testing through more research.
In the highly human managed landscapes of northwestern Europe, lacking the dynamics of ‘wilderness’ areas in North America and Eastern Europe (see for instance Kuijpers et al. 2013), the so-called landscape-of-fear effect is difficult to discern. Wolf habitat types include many forestry stands, drained mire and peat extraction areas, managed heathlands and hunted wildlife populations. The ecological processes in these modern and often small-scale European landscapes have become largely restricted or rigid, with only certain processes like population dynamics functioning properly. Only in areas where ecological processes are free to run and evolve in succession is the wolf likely to exert its ecological key-stone role that can bring about certain shifts in plant and animal communities; and even transform the character of landscapes.
As an opportunistic predator requiring certain habitat requirements as described, the wolf in northwestern Europe has so far demonstrated a role as a rewilding icon or flagship species in a spontaneous process of revival. This spontaneous rewilding process (Van Maanen & Convery 2016) with the wolf as prime indicator is passively facilitated by human land management, environmental change with subsequent ecological changes (including land abandonment), and actively through protection since the 1970s.
The return of the wolf inspires opportunities to revive a lot of the ecology (including the co-evolutionary relationship between large mammalian carnivores and herbivores) that has been lost in much of Europe. This is attainable if we loosen the reigns of our control on the ecology and learn to appreciate large carnivores as companions, rather than regard them as a threat to be avoided or curtailed.
The landscapes that the wolves inhabit currently in northwestern Europe are not wilderness areas, having been highly modified by human activities. However, these are landscapes where the human influence is waning – as demonstrated in Germany – and as a result show the re-emergence of wild elements or ‘wilding’ in places. Not only are wolves reinstating a key ecological role, but other flagship species long suppressed by humans are also emerging, including the eagle owl, osprey, sea eagle, otter, golden jackal and crane.
Acknowledgement: Constant companion in this study on wolves is Fokko Bilijam, to whom I am deeply grateful in sharing the ups-and-downs of wolf research, including joint wolf sightings; cause for celebration every time.
Notes and references
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Errington, P.L. 1967. Of predation and life. Iowa State University Press, Ames.
Faß, F. 2018. Wildlebende Wölfe: Schutz von Nutztieren – Möglichkeiten und Grenzen. Muller-Ruschlikon Verlag, Stuttgart.
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Klees, D., E. van Maanen, L. Linnartz, M. Drenthen & M. van der Weide 2015. De wolf terug. Eng of enerverend? Kosmos, Utrecht/Antwerpen.
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DBBW, die Dokumentations- und Beratungsstelle des Bundes zum Thema Wolf https://dbb-wolf.de/
 https://www.noz.de/lokales-dk/delmenhorst/artikel/552607/wolf-in-wohngebiet-weckt-bose-erinnerungen not mentioned in the formal statistics of wolf attacks on humans in the 19th Century by Linnell et al. 2002.