|North American beaver (Castor canadensis)|
Beavers (genus Castor) are large, semiaquatic rodents of the Holarctic realm. There are two extant species, the North American beaver (Castor canadensis) and the Eurasian beaver (C. fiber). Beavers are the second largest living rodents after the capybaras. They have stout bodies with large heads, long chisel-like incisors, brown or gray fur, dexterous front feet, webbed back feet and flat, scaly tails. The animals can be found in a number of freshwater habitats, such as rivers, streams, lakes and ponds. They are herbivorous and consume primarily tree bark, but may also eat aquatic plants, brush, grasses and sedges.
Beavers are known for building dams and lodges using tree branches, vegetation, rocks and mud; they chew down trees for building material. Dams impound water and lodges serve as shelters. Beavers are considered to be a keystone species, and their infrastructure creates wetlands used by many other species. Adult males and females live in monogamous pairs with their kits and yearlings. Beavers are highly territorial and mark them using scent mounts made of mud, debris and castoreum, a urine based substance excreted through the beaver's castor sacs.
Historically, beavers have been hunted for their fur, meat and castoreum. Castoreum has been used in medicine, perfume and food flavoring, while beaver pelts have been a major driver of the fur trade. Both species have been decimated because of overhunting, but protections begun in the 19th and early 20th centuries have allowed their populations to rebound. They are both listed as least concern by the IUCN Red List of mammals. The beaver is famed for its industriousness and its building skills, and is an official symbol of Canada.
The English word "beaver" comes from the Old English word beofor or befer (recorded earlier as bebr), which in turn sprang from the Proto-Germanic root *bebruz. Cognates in other Germanic languages include the Old Saxon bibar, the Old Norse bjorr, the Middle Dutch, Dutch and Low German bever, the Old High German bibar and the Modern German Biber. The Proto-Germanic word in turn came from the Proto-Indo-European (PIE) word *bhebhrus, a reduplication of the PIE root *bher-, meaning "brown" or "bright", whose own descendants now include the Lithuanian bebras and the Czech bobr, as well as the Germanic forms. The genus name Castor is Latin and derives from the Greek kastor which translates as "beaver" or "he who excels".
There are two extant species of beavers: the North American beaver (Castor canadensis) and the Eurasian beaver (C. fiber). Carl Linnaeus coined the genus Castor in 1758; he also classified the species name fiber. German zoologist Heinrich Kuhl classified C. canadensis in 1820. However, the two beavers were not shown conclusively to be separate species until chromosomal evidence did so in the 1970s. Prior to that, many still considered them the same species. The North American beaver has 40 chromosomes while the Eurasian beaver has 48. The North American beaver has a larger skull with a broader tail. 24 subspecies have been classified for C. canadensis while nine have been for C. fiber. The nostrils of the North American beaver are square shaped while those of the Eurasian species are triangular.
|Phylogeny of extant and extinct relatives of modern beavers.|
Beavers belong to the rodent suborder Castorimorpha along with Heteromyidae (kangaroo rats, kangaroo mice, pocket mice and spiny pocket mice) and the gophers. Modern beavers are the only extant members of the family Castoridae. Castoridae originated in North America in the late Eocene and dispersed into Eurasia via the Bering Land Bridge in the early Oligocene coinciding with the Grande Coupure, a time of great faunal turnover around 33 million years ago (mya).
The more basal castorids had features such as more complex occlusion between the cheek teeth, parallel upper tooth rows, premolars close to the molars in size, the presence of a third set of premolars (P3) and the stapedius muscle, smooth palatine bone with a posteriorly located palatine foramen and an elongated rostrum. More derived castorids have less complex occlusion, upper tooth rows which diverge posteriorly, larger second premolars compared to molars, loss of P3 and stapedius, and more grooved palatine with a palatine foramen shifted towards the front. Members of the subfamily Palaeocastorinae appeared in late Oligocene North America. This group was small-bodied and adapted to a fossorial or burrowing lifestyle, with relatively large forelimbs, a low, broad skull and short tail.
In the early Miocene (about 24 mya), castorids evolved a semiaquatic lifestyle and developed the ability to cut down trees and build infrastructure allowing them to survive in the harsh winters of Arctic latitudes. It appears that these behaviors started as a side effect to the consumption of wood and bark. Members of the subfamily Castoroidinae appeared around this time and included giants like Castoroides of North America and Trogontherium of Eurasia. Members of this group appear to have been less specialized for aquatic life than modern beavers.
There is evidence that at least one genus in Castoroidinae, Dipoides, ate bark and built dams and lodges. Researchers suggest that eating bark and building are unlikely to have evolved twice, so modern beavers and Castoroidinae shared a wood-eating common ancestor. Dipoides appears to have been a rather poor builder compared to modern beavers. The genus Castor likely originated in Eurasia, and the ancestors of the North American beaver would have entered North America across the Bering Land Bridge in the late Miocene (8–7.6 mya). The lineages of the two beaver species are roughly estimated to have split around 7.5 mya. The Eurasian beaver may have descended from C. praefiber. C. californicus was similar to but larger than the extant North American beaver.
Characteristics and adaptations
Beavers are the second largest living rodents after the capybaras. They have a head-body length of 80–120 cm (31–47 in), with a 25–50 cm (9.8–19.7 in) tail, a shoulder height of 30–60 cm (12–24 in) and a weight of 11–30 kg (24–66 lb). Their bodies are drop-shaped like other aquatic animals. A beaver coat has 12,000–23,000 hairs/cm³ and functions to keep the animal warm, help it to float in water and to protect against the teeth and claws of predators. Guard hairs are 5–6 cm (2.0–2.4 in) long and typically reddish brown, but can range from yellowish brown to nearly black; while the underfur are 2–3 cm (0.79–1.18 in) long and dark gray. Beavers molt during the summer.
Beavers have massive skulls adapted for withstanding the forces generated by their powerful chewing muscles. Their four incisors are chisel-shaped with continuous growth. The outer enamel of the incisors is very thick and colored orange due to the presence of iron. The roots of the lower incisors extend throughout the length of the lower jaw. Beavers have four premolars and 12 molars adding up to 20 teeth in total. The molars have meandering ridges on a flat surface for grinding woody food. The eyes, ears and nostrils are arranged so that they can remain above water when the rest of the body submerges. The nostrils and ears have valves that close underwater while nictitating membranes cover the eyes. Their lips can close behind the incisors, allowing for chewing in water. Beavers typically spend five to six minutes underwater per dive, but they can hold their breath for as long as 15 minutes.
The beaver's front feet are dexterous, allowing them to grasp and manipulate objects as well as dig and groom. The hind feet are larger and have webbing between the toes which they use for swimming. The second claw of the hind foot is split and is used for combing the fur to keep it fluffy. Perhaps the most distinctive feature of the beaver is its flat, scaly tail which has multiple functions. It props up the animal when it is cutting down a tree and acts as a rudder when it is swimming and maneuvering underwater. It also stores fat and has a countercurrent blood vessel system which allows the animal to reduce heat loss by 25% during the summer and two percent in the winter. Despite popular depictions, beavers do not use their tails to pack or carry mud.
The beaver's digestive system is adapted for a high-fiber diet; a cardiac gland secretes into the stomach. Its intestine is six-times longer than its body and the caecum is twice the volume of its stomach. The beaver's fecal matter takes the form of balls of sawdust, which it deposits into the water. The beaver's sex organs are located within the body. Beavers have one opening, a cloaca, that contains the genital, digestive and excretory openings. This may serve to reduce areas for infections when swimming in dirty water. Beavers have a pair of castor sacs found between the kidneys and urinary bladder and open into the urethra and anal glands. The castor sacs secrete castoreum, a urine-based substance used mainly for marking territory. Anal glands produce an oily substance which beavers use to rub on their fur to make it waterproof. It also plays a role in individual and family recognition.
Compared to many other rodents, the brain of a beaver has a smaller hypothalamus in relation to the cerebrum, with a ratio of hypothalamus to cerebrum length ranging from 0.20 to 0.24; this indicates a relatively advanced brain with higher intelligence. The cerebellum is well-developed, giving the beaver coordination in three-dimensional space (such as underwater). The neocortex is dedicated mainly to touch and hearing. The former is more advanced in the lips and hands than the whiskers and tail. Vison in the beaver is comparably poor, and the beaver eye is not as well adapted to seeing underwater as that of an otter. Beavers have an acute sense of smell which is particularly important for sniffing out scent marks as well as detecting land predators.
Distribution and status
The IUCN Red List of mammals lists both beaver species are as least concern. The North American beaver is widespread throughout the continent down to northern Mexico; being absent only in the Arctic, the deserts of the southwestern US and in peninsular Florida. The species was introduced to Finland and spread to other parts of Europe (and coexists with the Eurasian species), the Russian Far East, and Tierra del Fuego, Patagonia. Historically, the North American beaver was trapped and almost extirpated because its fur and castoreum were highly sought after. With protections in the late 19th and early 20th centuries, the beaver population had rebounded to an estimated 10 to 15 million by the early 21st century; this is a fraction of the originally estimated 100 to 200 million North American beavers before the days of the fur trade.
The Eurasian beaver's range is less contiguous. It was historically widespread throughout Europe and Asia, but overhunting greatly reduced its range by the early 20th century. In Europe, beavers were reduced to isolated populations in the Rhône of France, the Elbe in Germany, southern Norway, the Neman river and Dnieper Basin in Belarus and the Voronezh river in Russia with combined numbers estimated at 1,200 individuals. The beaver has since returned to parts of its former range because of management measures and reintroductions. Beaver populations now range from Spain and France, through central and eastern Europe and into Scandinavia and western Russia. Beginning in 2009, beavers have also been reintroduced successfully to parts of Great Britain. In 2020, the total beaver population in Europe was estimated at over one million. Small populations are also present in Mongolia and northwestern China, their numbers estimated at 300 and 700 respectively as of 2016. Under New Zealand's Hazardous Substances and New Organisms Act 1996, beavers are classed as a "prohibited new organism" preventing them from being legally imported into the country.
Beavers live in freshwater ecosystems like rivers, streams, lakes and ponds. Water is the most important part of beaver habitat, and they require a yearly supply that is sufficient for swimming, diving, floating logs, protection of lodge entrances and safety from land-dwelling predators. Beavers are cautious on land and escape into the water when they sense a threat. With streams, beavers prefer to use slow-moving water, typically with a gradient or steepness of one percent, though they have been recorded using streams with gradients as high as 15%. Wider streams around 8 m (26 ft) are used more than narrower ones in the 1.4 m (4 ft 7 in) range. Beavers typically avoid areas with regular flooding and may abandon a location for years after a significant flood.
Beavers prefer areas with flatter terrain but can be found in mountainous areas. They need trees and shrubs to build lodges and dams. Dispersing beavers will use certain habitats temporarily before arriving at their final destinations, particularly in spring. These include small streams, temporary swamps, ditches and even backyards. These sites lack important resources, and the animals do not remain there for long. Beavers have increasingly settled at or near human-made environments, including agricultural areas, suburbs, golf courses and even shopping malls.
Beavers have an herbivorous and a generalist diet. They eat mainly eat tree bark. They can fall trees in an average of 1.24 minutes, but this can depend on the circumference of the trunk. Those 25 cm (9.8 in) and larger require over four hours. North American beavers prefer aspen trees while Eurasian beavers prefer willow. Both tree species grow quickly and have soft wood for chewing and peeling. North America beavers can colonize an area where aspen is around 60 m (200 ft) from the water but can harvest trees several hundred meters away. Beavers do harvest other tree species like maples, alders, cherry, beech and hornbeam. Non-woody plants consumed include aquatic plants like water-shields and lilies, and ferns, raspberries, grasses and sedges. Canids, felids and bears prey upon beavers. Their parasites include the bacteria Francisella tularensis which causes tularemia, the protozoan Giardia duodenalis which causes Giardiasis or "beaver fever", as well as the beaver beetle and mites of the genus Schizocarpus. They have also been recorded with the rabies virus.
Beaver dams impound flowing water eventually submerging the entrance to their homes. The enclosed water enables the floating of building material, and provides depth for diving to safety and a wider area for feeding. Lake-dwelling beavers do not need to build dams. Dams consist of logs, rocks, wads of grass and mud. They can be as low as 20 cm (8 in) to as high as 3 m (10 ft) tall and can stretch 0.3 m (1 ft 0 in) to several hundred meters long.
Water flow determines how a beaver builds a dam. In shallow stagnant water, the animals slowly build up mud, leaves and small twigs. Large streams require a more solid base. Beavers use log poles, around 2 m (6 ft 7 in) long and 5 cm (2.0 in) in diameter, to brace against the banks. These are aligned in the direction of the water's flow at an angle of 30 degrees. Heavy rocks weigh down the poles, and grass is stuffed between them. Beavers continue to pile on more material until the dam settles into a compact slope on the enclosed side.
Beavers use shelters or lodges for protection from the weather and predators, and as sites for eating, resting, sleeping, mating, birthing and rearing. They may dig tunnels or bank holes into steep-sloped banks with entrances underwater. In some cases, they may pile sticks over and around the entrance, creating bank lodges. The most complex are freestanding open-water lodges that are built over a platform in shallow water consisting of sturdy logs and mud. Their entrances are submerged, and the roof is sealed up with mud apart from an air vent at the top.
All types of lodges can be present at a beaver site. During the summer, beavers tend to use bank lodges which are cooler than the surrounding air. Open-water lodges are used during the winter; their temperature is similar to that of the surrounding water. An air vent provides ventilation, and carbon dioxide can clear out in 60 minutes. The amount of oxygen and carbon dioxide in a lodge does not change much with the seasons. During the winter, warm air coming out of the vent helps melt the snow and ice on the lodge.
Beaver lodges built by first-time settlers are typically small and sloppy. More experienced families can build structures that are 6 m (20 ft) in diameter and 2 m (6 ft 7 in) high. Lodge building takes place mainly at night. One sturdy enough to withstand the coming winter can be built in just two nights. Dams and lodges built by North American beavers tend to be more advanced. Eurasian beavers tend to build more bank lodges while North American beavers build more open-water ones. Beavers cache their food for the winter, piling up branches and saplings next to their lodge.
Beavers create trails as they wander onto land and wear down vegetation, particularly by dragging tree limbs back to the water. If the ground is level, these trails may fill with water, becoming canals. Beavers will make them deeper by digging up mud. These trails can stretch 15–18 m (49–59 ft), or even longer in tree depleted areas. Canals can make transporting logs to the pond easier. Beaver families may also dig channels at the bottom of their pond, which can retain water during a drought.
The beaver works as a keystone species in an ecosystem by creating wetlands used by many other species. Next to humans, no other extant animal appears to do more to shape its landscape. When building dams and lodges, beavers alter the paths of streams and rivers and allow for the creation of extensive wetland habitats. Beaver ponds, and the wetlands that succeed them, remove sediments and pollutants from waterways, including total suspended solids, total nitrogen, phosphates, carbon and silicates. One study found that beaver engineering leads to a 33 percent increase in the number of herbaceous plant species on river banks. Another study found the presence of beavers can increase wild salmon populations; their dams has been shown to have a positive effect on trout by increasing their numbers, their size, or both. Contrary to popular myth, most beaver dams do not pose barriers to trout and salmon migration, although fish movement may be restricted seasonally during periods of low stream flows.
Beavers help waterfowl by creating increased areas of water. In northerly latitudes, beaver activity in ponds warms the water, causing ice to thaw earlier than those without beaver, allowing Canada Geese to nest earlier. In a study of Wyoming streams and rivers, watercourses with beavers had 75-fold more ducks than those without. The widening of the terrace beside streams associated with beaver dams has been shown to increase the abundance and diversity of birds favoring river banks, an impact that may be especially important in semi-arid climates. As trees are drowned by rising beaver impoundments, they become ideal nesting sites for woodpeckers, which carve cavities that attract many other bird species. Fish-eating birds use beaver ponds for foraging, and in some areas certain species appeared more frequently where beavers were active than at sites with no beaver activity. Beaver modifications to streams in Poland have been associated with increased bat activity. While overall bat activity was increased, Myotis bat species, particularly Myotis daubentonii, activity may be hampered in locations where beaver ponds allow for the increased presence of duckweed.
Introduced Beavers at Tierra del Fuego have destroyed around sixteen million hectares of indigenous forest. Unlike many trees in North America, trees in South America rarely regenerate when cut down. Ponds flooded by beavers lead to the growth of other trees and vegetation. With no natural predators, the animals have spread beyond Tierra del Fuego into Chile's Brunswick Peninsula, and the government fears further penetration into continental South America. However, areas with introduced beaver were associated with increased populations of native puye fish (Galaxias maculatus).
Beavers may contribute to climate change. The structures they build can flood valleys and form lakes. In Arctic areas, these can cause permafrost to thaw releasing methane into the atmosphere. The beavers' recent migration and habitation in the Alaskan tundra is escalating this phenomenon.
Beavers are mainly nocturnal. They spend the daytime in their shelters. During the first half of the night they forage; they do construction work in the second half. In some areas, beaver activity is decoupled from the 24-hour cycle. Particularly during winter, when confined to their lodge, they may have an activity-cycle of as much as 28 hours.
The basic unit of beaver social organization is the family comprising an adult male and adult female in a monogamous pair and their kits and yearlings. Beaver families can have as many as ten members in addition to the monogamous pair. Groups this size, or close to this size, build more lodges to live in while smaller families usually need only one. However, large families have been recorded living in one lodge. Beaver pairs mate for life; however, if a beaver's mate dies, it will partner with another one. Extra-pair copulations can occur. Females may have their first estrus cycle of the season in late December and peak in mid-January. Females may enter estrus two to four times per season, and each cycle lasts 12–24 hours. Mating typically takes place in the water but may also occur in the lodge and lasts 30 seconds to three minutes. Gestation lasts between 104 to 111 days, with three or four kits being born.
Both males and females take part in raising offspring. After they are born, the young spend their first month in the lodge; their mother is the primary caretaker while their father maintains the territory. After they leave the lodge for the first time, yearlings will help their parents build food caches in the fall and repair dams and lodges. Adults do most of the work. Young beavers help their parents but depend on them for food and teaching them life skills. They spend most of their time playing but also copy their parents' behavior. While copying behavior helps imprint life skills in young beavers, it is not necessarily immediately beneficial for parents as the young beaver do not perform the tasks as well as adults. Beaver kits are weaned at ten weeks.
Older offspring, around two years old, may also live with families and help their parents. In addition to building food caches and repairing the dam, two-year-olds will also help care for younger offspring. While they help to increase the chance of survival for younger offspring, they are not essential for the family. Two-year-olds stay and help their families only if there is a shortage of resources in times of food shortage, high population density, or drought. Beavers typically leave their parental colony at 23 months old, and usually settle nearby. Beavers recognize their kin by using their keen sense of smell to detect differences in anal gland secretion composition. Related beavers share more features in their anal gland secretion profile than unrelated beavers. Being able to recognize kin is important for beaver social behavior, and it leads to more tolerant behavior among neighboring beavers.
Within the lodge, beavers communicate with burps and whines. They produce gargles and bubbles when entering and exiting. When outside, tail-slaps, which involve an animal hitting the water surface with its tail, serve as alarm signals warning of a potential threat. The tail slap of an adult is more successful in alerting the entire family, which then escape into the lodge. Adults normally ignore those of juveniles who have not yet learned the proper use of a tail-slap.
Territories and spacing
Beavers maintain and defend territories which contain dams, canals, trails and food caches while the outside feeding areas are encompassed within a home range. They invest much energy in their territories, building their dams and becoming familiar with the area. Beavers mark their territories by constructing scent mounts made of mud, debris and castoreum. Most of these are near the border of their territory.
Because they invest so much energy in their territories, beavers are intolerant of intruders, and the territory holder is more likely to escalate an aggressive encounter. Aggressive and defensive beavers will hiss and encounters are often violent. To avoid such situations, a beaver marks its territory with as many scent mounds as possible, signaling to intruders that the territory holder has enough energy to maintain its territory and can put up a good defense. Territories with more scent mounts are avoided more often than ones with fewer mounts. Scent marking increases in spring during the dispersal of yearlings to deter intruders.  Beavers also exhibit a behavior known as the "dear enemy effect". A territory-holding beaver will investigate and become familiar with the scents of its neighbors. They respond less aggressively to intrusions by their territorial neighbors than those made by non-territorial floaters or "strangers".
Interactions with humans
Beavers sometimes conflict with humans over land use. The water impounded by dams can damage crops, tree plantations, roads and recreational areas. The water held by dams can be dangerous if the structure breaks too quickly. Beavers may also consume crops and fell economically important trees. Relocation or culling is used to control "nuisance beavers". Beavers occasionally attack humans and domestic pets, particularly when infected with rabies, in defense of their territory, or when they feel threatened. At least one beaver attack on a human is known to have been fatal: a 60-year-old fisherman in Belarus died in 2013 after a beaver bite opened an artery in his leg. There are also records of fatal beaver attacks on dogs. Humans may contract 'beaver fever' from the animals when they drink water inhabited by them. Human activities are actually more responsible for contamination of water by Giardia.
Beavers have been hunted, trapped and exploited for their fur, meat and castoreum. Castoreum was used for a variety of medical purposes; Pliny the Elder suggested that it could treat vertigo, seizures, flatulence, sciatica, stomach diseases and epilepsy. He also stated it could cure hiccups when mixed with vinegar, toothaches if mixed with oil and injected into the ear on the same side as the tooth and could be used as an antivenom. The 1911 British Pharmaceutical Codex described castoreum for use in dysmenorrhea and hysterical conditions (i.e. pertaining to the womb), for raising blood pressure and increasing cardiac output. The activity of castoreum has been credited to the accumulation of salicin from willow trees in the beaver's diet, which is transformed to salicylic acid and has an action very similar to aspirin.
The musky odor of the substance has also lent itself as an ingredient in perfumes and for use in food flavorings. Ancient people appear to have believed, falsely, that the castor sacs of the beaver were its testicles. Aesop's Fables describes beavers chewing off their testicles to preserve themselves from hunters, (which is impossible because a beaver's testicles are inside its body); this myth has persisted for centuries. The Catholic Church traditionally considered the beaver to be part beast and part fish. The Church allowed the scaly, fish-like tail to be eaten on meatless Fridays during Lent. Beaver tails were a delicacy in medieval Europe and were described as having the flavor of a nicely dressed eel.
Beavers were also hunted for their fur. Hunters and trappers could easily find them since they stayed in one place and would kill entire families in a lodge. The fur trade in North America was built mainly on the beaver and pelts were valuable enough to cause or contribute to the Beaver Wars, King William's War and the French and Indian War. Fur traders were the main driver of the westward expansion of Europeans into the continent, and fur traders were the first to meet and negotiate with the native peoples, who capitalized on trading with the Europeans. Between 1860 and 1870, the peak of the fur trade, the Hudson's Bay Company and fur companies in the US bought over 150,000 beaver pelts per year. They were used mainly to make hats, which were considered a luxury item in 17th century England and were commonly stolen. Conservation, anti-fur and animal rights campaigns have lowered the demand for beaver pelts and the global fur trade is no longer profitable. In modern times, beavers are mainly hunted for recreation and population management.
In wider culture, the beaver is famed for its industriousness and its building skills. They have also lent themselves to everyday language. The English verb "to beaver" means to work hard and constantly, and a "beaver intellect" refers to a slow but honest mentality. The name "beaver" is also a slang term for beards and the female genitalia.
In a Haida tale, a raven tried to steal salmon from beavers by rolling up their stream like a carpet but had to keep stopping to rest in treetops. The beaver followed and kept gnawing down the trees, causing the raven to keep losing fish and water. In a Cree story, the trickster Wisakedjak hacked at the lodge and dam of the Great Beaver. However, the beaver used its power to stop the water from rushing though and caused the water to build up and flood the world.
Medieval European art often depicted beavers fantastically, sometimes looking dog like, given dagger-like tusks or even fish tails. They were identified as beavers by being given visible testicles. Beavers also appear in Dante Alighieri's Divine Comedy and in the writings of Athanasius Kircher, who wrote that when the beavers entered Noah's Ark they were given a stall near to a water-filled tub which they shared with mermaids and otters. The anthropomorphic Mr. and Mrs. Beaver have an important role in the plot of The Lion, the Witch and the Wardrobe, the first book in C. S. Lewis' The Chronicles of Narnia. Animated series like The Angry Beavers and Happy Tree Friends have featured beavers.
The importance of the beaver in the development of Canada through the fur trade led to its official designation as the national animal in 1975. The animal has long been associated with Canada, appearing on the coat of arms of the Hudson's Bay Company in 1678. It is depicted on the Canadian five-cent piece and was on the first pictorial postage stamp issued in the Canadian colonies in 1851 (the so-called "Three-Penny Beaver"). The city of Montreal and the Canadian Pacific Railway bear the beaver on their crest or coat of arms. The beaver has been used in heraldry in Europe, including the coats of arms of the city of Biberach and the University of Oxford.
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