Dogs Atlas
Black and tan German Shepherd standing alert, side view

German Shepherd

The German Shepherd is a large German herding dog, created from regional shepherd dogs in the 1890s and registered as a breed from 1899 by Captain Max von Stephanitz.

He wanted a working dog first and a show dog second. The breed went on to become the classic police, military, search and guide dog, and two early film stars, Strongheart and Rin Tin Tin, made it famous worldwide. It suits active owners who can give it training, a job and more than two hours of daily activity, and it is a poor fit for homes that leave a clever, sensitive dog idle.

German Shepherd quick facts

Related breedDobermann1880 to 1900 · Germany
Height60 to 65 cmFCI
Weight30 to 40 kgFCI
Life span9 to 13 yearsproject data
Exercise2+ hours a dayKennel Club
Closest DNA relatives
Cane Paratore, Berger Picard, Chinook, Xoloitzcuintle, Belgian Malinois
Sister breeds
Belgian Shepherd, Dutch Shepherd
Country of origin
Germany
Period of development
1899 (project data: first breed registry and standard)
Foundation sire
Horand von Grafrath (born Hektor Linksrhein, 1895), number SZ 1
Founder
Max von Stephanitz (1864 to 1936)
Type
Herding dog (FCI Group 1, Sheepdogs and Cattledogs; FCI standard no. 166; AKC Herding Group; UK Kennel Club Pastoral Group)
Height
FCI: dogs 60 to 65 cm, bitches 55 to 60 cm. UK Kennel Club: ideal 63 cm and 58 cm
Weight
FCI: dogs 30 to 40 kg, bitches 22 to 32 kg. UK VetCompass adult median: 40.1 kg males, 34.8 kg females
Coat
Two varieties: double coat (standard) and long and harsh outer coat (long coat). Dense undercoat in both
Colours
Black with tan, red-brown or light markings (saddle), (grey), solid black, bi-colour. White is not allowed under the FCI standard
Life span
Project data: 9 to 13 years. UK VetCompass median: 10.3 years. SV: 10 to 12 years
Exercise
More than 2 hours a day (UK Kennel Club breed information)
DNA group
"New World" (Parker et al. 2017)

Name and origin

Related breedGreater Swiss Mountain Dog1700 to 1909 · Switzerland

The German name is Deutscher Schäferhund: Schäfer means shepherd and Hund means dog. "German Shepherd" is a direct translation, and "German Shepherd Dog" is the official name used by the FCI, the AKC and the UK Kennel Club.

The breed was also called the "Alsatian" in Britain for about six decades. After the First World War, the name "German" was seen as a handicap. British breeders and the Kennel Club adopted "Alsatian Wolf Dog", after Alsace, a border region that had been German from 1871 and returned to France after the war. "Wolf Dog" was later dropped because it frightened people and raised hybrid concerns, leaving "Alsatian". The Kennel Club allowed the original name back in 1977, and Wikipedia reports that "Alsatian" stayed in brackets in the official UK name until 2010.

Sources disagree on dates. The German Shepherd Dog Club of America says the British change came in 1917, in the same wave as the American one. Other histories place the UK change at the end of the war, with British registrations starting in 1919. In the United States, the American Kennel Club dropped "German" in 1917 (breed name "Shepherd Dog") and restored "German Shepherd Dog" in 1931.

History

Same eraPumi1700 to 1923 · Hungary

Before 1899

Herding dogs were common across central Europe for centuries, and they differed by region. Stephanitz worked with dogs from Thuringia in the north, Franconia and Württemberg in the south. He was a former cavalry officer (captain from 1898) who had studied at the Veterinary College in Berlin, and he wanted to combine the best working traits of these regional types into one standardised dog.

Stephanitz and Horand

In April 1899, at a dog show in Karlsruhe, Stephanitz saw a dog called Hektor Linksrhein, born on 1 January 1895 and bred by Friedrich Sparwasser. He bought him for a reported 200 marks, renamed him Horand von Grafrath and registered him as number 1 in the new stud book (SZ 1). Horand is treated as the first German Shepherd.

The same month, Stephanitz and his friend Artur Meyer founded the Verein für Deutsche Schäferhunde (SV, Society for German Shepherd Dogs). The SV and Wikipedia agree on 22 April 1899. They differ on the place: the SV names Karlsruhe, while Wikipedia says the club was formally set up with headquarters in Stuttgart after the decision was made at Karlsruhe. Stephanitz led the SV as president until 1935.

Horand's best-known son was Hektor von Schwaben. Breeding Hektor with Horand's other offspring produced Heinz von Starkenburg, Beowulf and Pilot, and this heavy was used to fix the traits Stephanitz wanted. The SV's founding standard put work before looks: a pleasing appearance is desirable, but it must not put working ability in question. The FCI still requires a working trial for the breed.

Two world wars

Stephanitz promoted the dog as a service animal, and the First World War gave him the proof. The SV reports that about 7,000 German Shepherds were lost serving as messengers, cable layers and medical dogs. Membership grew fast afterwards: Wikipedia quotes 50,000 dues-paying members in more than 500 branches in 1923. Stephanitz left the SV in 1935 during the Nazi period and died on 22 April 1936 in Dresden.

The Second World War hit the breed hard. The SV lists thousands of German Shepherds used as messengers, gas detectors and ammunition , and membership stood at about 40,000 in 1949. A 2026 genome study (Scarsbrook et al., see Health) traces later bottlenecks to this post-war period.

Police, military and guide dogs

  • Police. Ghent, Belgium, ran the first organised police dog service in 1899. The German police then chose the German Shepherd as the preferred breed, and the Prussian state opened a police dog training school at Grünheide in 1920.
  • Military. Shepherds served as messenger, sentry, scout and rescue dogs in both world wars and have stayed in military work since.
  • Guide dogs. Germany set up the first guide dog schools during the First World War for soldiers blinded in the war. In 1927 the American breeder Dorothy Harrison Eustis, then living in Switzerland, wrote "The Seeing Eye" in The Saturday Evening Post about the school at Potsdam. Morris Frank, a blind 19-year-old from Nashville, read it and wrote to her. In April 1928 he received a German Shepherd female named Kiss, renamed Buddy. The Seeing Eye was founded in Nashville on 29 January 1929, and its early dogs were German Shepherds. Labradors and Golden Retrievers now dominate guide dog work.

Film stars

  • Strongheart. Born Etzel von Oeringen in 1917 in Breslau and trained in Berlin as a police dog. Brought to the US about 1920, his first film, The Silent Call (1921), made him the first major canine film star. He died on 24 June 1929 in Los Angeles and has a star on the Hollywood Walk of Fame.
  • Rin Tin Tin. Found as a puppy in September 1918 in a bombed German kennel at Flirey, France, by the American corporal Lee Duncan. He appeared in 27 Hollywood films between 1922 and 1931, and his 1923 film Where the North Begins has often been credited with saving Warner Bros. from bankruptcy. He died on 10 August 1932.

Kennel club recognition

YearEvent
1899SV founded (22 April) and Horand entered as SZ 1
1908First German Shepherd registered with the AKC (GSDCA history)
1913German Shepherd Dog Club of America founded, 26 charter members
1917AKC drops "German": breed listed as "Shepherd Dog"
1919UK registrations begin under the name Alsatian Wolf Dog: 54 dogs, rising to over 8,000 by 1926 (Wikipedia)
1931AKC restores the name "German Shepherd Dog"
1977UK Kennel Club allows "German Shepherd Dog" again
2010Current FCI standard no. 166 (German original 23 March 2010; English version 23 December 2010)

The FCI lists the breed as definitive, standard no. 166, country of origin Germany. The SV says its stud book now holds more than 2 million dogs, and it calls itself the world's largest breed club with over 50,000 members.

Relatives and DNA

Same familyBoxer1880 to 1904 · Germany

Ancestors and sister breeds. The German Shepherd has no documented parent breed. It was assembled from the regional shepherd dogs of Thuringia, Franconia and Württemberg in the late 1890s, so the project knowledge base treats it as a foundation breed. The Belgian Shepherd and the Dutch Shepherd come from the same Western European herding type and diverged in the same period, so they are siblings rather than parent and child. The Belgian Malinois, a coat variety of the Belgian Shepherd, often works alongside the German Shepherd in police and military units.

Varieties and offshoots

  • White Shepherd. North American variety bred from white-coated German Shepherds. White dogs existed in Europe from 1882, and the German standard was amended in 1933 to ban them from registration. North American and Canadian enthusiasts set up their own club in 1969.
  • White Swiss Shepherd Dog. Descends from White Shepherds imported from North America from the early 1970s and is now a separate breed in Switzerland.
  • King Shepherd and Shiloh Shepherd. US varieties developed from German Shepherds in the 1970s to 1990s.
  • East European Shepherd. Bred in the Soviet Union from German Shepherds imported to Ukraine in the 1920s.
  • Saarloos Wolfdog (Netherlands) and Czechoslovakian Wolfdog. Leendert Saarloos crossed a German Shepherd with a Siberian wolf in 1935. Colonel Karel Hartl began the Czechoslovakian programme in 1955 with German Shepherds and Carpathian wolves; the first hybrids were born in 1958, and the FCI accepted the breed definitively in 1999.

Breeds that used German Shepherd blood. The Chinook (Arthur Walden crossed his sled lead dog with German Shepherds and others), the Hovawart, the Akita (crossed with German Shepherds during the Second World War to avoid culling), and the Northern Inuit and Tamaskan dogs. The project database counts 22 descendant breeds in total, many of them outcross contributions, not direct descendants.

What does DNA say?

A 2017 study by Parker and colleagues (Cell Reports) analysed 1,346 dogs from 161 breeds and sorted them into 23 supported clades. The German Shepherd falls in the "New World" clade, where the signal centres on the German Shepherd. The study also measured shared : long stretches of identical DNA from common ancestors. The more (Mb) two breeds share, the stronger the sign of crossing or shared founders. The study cannot say which way the genes flowed.

Source: Parker et al. 2017, as recorded in this site's breed database.

Three results stand out. The Chinook's 122 Mb fits its documented crossing with German Shepherds. The Berger Picard and the rare Italian Cane Paratore share just as much, and the project data has no documented crossing for either, so this is a signal for researchers to explain, not a proven pedigree. The Belgian Malinois shares 42.6 Mb, which matches the history of the two breeds working side by side.

The family at a glance

Sister breeds · 2

Descend from it · 17

Shared DNA with the German Shepherd
Even the closest relative shares a small slice: 124.2 Mb of a genome of about 2,400 Mb.

Source: Parker et al. 2017. Percent of the whole genome.

Breedwith German ShepherdShared DNA with German Shepherd (Mb)Shared DNA (Mb)
Cane Paratore124.2
Berger Picard123.9
Chinook122.2
Xoloitzcuintle64.2
Belgian Malinois42.6
Peruvian Hairless Dog35.6
Portuguese Water Dog28.7
Leonberger26.4
Maremmano-Abruzzese Sheepdog18.9
Australian Shepherd14.8
Dobermann14.8
Greater Swiss Mountain Dog13.5
Pumi10.6

The breed standard

Looks relatedBullmastiff1860 to 1924 · United Kingdom

A breed standard is the written ideal that kennel club judges compare each dog against. The German Shepherd standards describe a dog slightly longer than tall, with strong muscles, a weather-resistant coat and a far-reaching, enduring trot. The sources used here give full figures for the FCI and the UK Kennel Club; AKC figures are not quoted.

TraitFCIUK Kennel Club
HeightDogs 60 to 65 cm, bitches 55 to 60 cmIdeal 63 cm and 58 cm, 2.5 cm either way tolerated
WeightDogs 30 to 40 kg, bitches 22 to 32 kgNone given (VetCompass adult median: 40.1 kg males, 34.8 kg females)
Head and eyesWedge-shaped, muzzle about half the head length; eyes medium, almond-shaped, dark brown preferred
EarsMedium, broad at the base, erect and nearly parallel; hanging ears are a fault
BuildDeep chest, short loin, straight back to a gently sloping (about 23 degrees to the horizontal) straight from neck over the withers, falling slightly to a gently sloping croup
Coat varietiesStandard double coat (short, hard, thick undercoat) and long coat (ear tufts, feathering); both acceptedBoth described; long coat is and rarer
ColoursBlack with tan, gold or light grey markings (saddle), all black, grey sable, bi-colour; white not allowedBlues, livers, whites and near-whites highly undesirable

Working lines, show lines and the sloping back

Two kinds of German Shepherd now coexist: working lines, selected through work trials, and show lines, selected in the ring. Working-line dogs tend to have a flatter back and a more upright rear. Some show-line dogs, especially in the UK and North America, carry a strongly sloping topline with heavily angled hind legs. The standards ask for a straight back, and the current UK text says the dog should be balanced and free from exaggeration.

The debate is well documented:

  • The BBC documentary Pedigree Dogs Exposed (19 August 2008) criticised the show lines for their hindquarters.
  • In March 2016 a German Shepherd with a sloped back and apparent walking difficulty won Best of Breed at Crufts. The Kennel Club's health chair said he was "appalled" (MRCVSonline, 16 March 2016).
  • In 2018 the Kennel Club listed the breed in Breed Watch category 3 (visible conditions or exaggerations that cause pain or discomfort). Its current breed page lists the breed as category 2 with "conformational concerns".
  • A 2020 study (Humphries, Shaheen and Gómez Álvarez, Scientific Reports) measured 60 German Shepherds with 3D motion capture and pressure plates. Dogs with a greater back slope placed their forelimbs closer together, loaded the forelimbs more at the trot, and showed more asymmetric movement at the hock and stifle. The study shows association, not proof of disease, and it did not follow the dogs over their lives.

Temperament

Related breedChihuahua1850 to 1904 · Mexico

The UK Kennel Club describes a dog that is "steady of nerve, loyal, self-assured, courageous and tractable", never nervous, over-aggressive or shy. The SV describes it as secure, self-confident, attentive and physically and mentally resilient. The AKC puts it as loyal, confident, courageous and steady.

In daily life that means a dog that bonds closely with its people, watches its surroundings and is reserved with strangers. This steady temperament depends on early socialisation and consistent training. A fearful or under-socialised German Shepherd can become a reactive dog, which is also where most bite risk comes from.

In a large UK study (VetCompass, O'Neill et al. 2017, 12,146 dogs), aggression was recorded in 4.76 percent of German Shepherds over the study year, about 1 in 21 dogs, and more often in males (6.75 percent) than in females (2.78 percent). This is aggression noted by vets in clinical records, not a bite rate. Temperament also varies by line and by individual: Morrill and colleagues (Science, 2022) surveyed owners of 18,385 dogs and found that breed explains about 9 percent of behavioural variation between individual dogs. Ask a breeder about both parents' behaviour as well as their titles.

Work and training

  • Training. The SV says training is absolutely necessary, with consistency, patience and positive reinforcement rather than force.
  • Jobs and sports. Tracking, obedience, (formerly Schutzhund) protection sport, agility, search and rescue, scent work and herding all suit the breed. IGP began in Germany in the early 1900s as a test of breed suitability.
  • Scent work. Hall and colleagues (Journal of Comparative Psychology, 2015) found pugs learned an odour discrimination task better than German Shepherds. The breed's place in detection work rests on trainability, stamina and drive, not on the best nose.

Health

Related breedFlat-coated Retriever1860 to 1880 · United Kingdom

Most German Shepherds live active lives into their senior years. The points below are what breeders screen for and what owners can watch for. Information here is general. Talk to a vet about your own dog.

In the largest UK study, the VetCompass analysis by O'Neill, Coulson, Church and Brodbelt (Canine Genetics and Epidemiology, 2017), the median age at death was 10.3 years (range 0.2 to 17.0). Females lived longer (11.1 years) than males (9.7 years). The most common causes of death were musculoskeletal disorder (16.3 percent), inability to stand (14.9 percent), neoplasia (14.5 percent) and spinal cord disorder (13.6 percent).

For breeders, the UK Kennel Club recommends hip and elbow screening, a DNA test for and eye screening.

ConditionWhat it isHow commonWhat helps
Ear infections (otitis externa)Inflamed ear canalAbout 1 in 13 dogs in a year (7.89 percent; VetCompass 2017)Regular ear checks and vet care
OsteoarthritisWorn, stiff joints, mostly in older dogsAbout 1 in 18 dogs (5.54 percent; VetCompass 2017)Healthy weight, joint checks, vet pain management
OverweightExtra body weight that loads the jointsAbout 1 in 19 dogs (5.18 percent; VetCompass 2017)Measured meals, daily exercise
Joint malformation of the hip. BVA/KC scheme, 2025 edition, scores both hips; lower is better5-year median score 11, mean 14 (2,448 dogs scored in 5 years; 9,724 over 15 years)Hip scoring of both parents; healthy weight
Joint malformation of the elbowNo rate in the sources usedElbow scoring of both parents (UK Kennel Club, SV)
Degenerative myelopathy (DM)Late-onset progressive spinal cord disease in older dogs; SOD1 c.118G>A mutation, the same gene involved in some human ALS (Awano et al. 2009)In a small UK referral sample, 8 of 50 young dogs had two copies, about 1 in 6 (Holder et al. 2014); the German Shepherd is among the breeds with the highest frequency (Zeng et al. 2014, 33,747 dogs)DNA test of both parents
Gastric dilatation-volvulus (bloat)Emergency twisting of the stomach in deep-chested dogsSignificantly raised risk in German Shepherds among large breeds (Glickman et al. 2000)Know the signs; seek a vet at once. Feed smaller meals
Exocrine pancreatic insufficiency (EPI)The pancreas does not make enough digestive enzymes, causing weight loss and diarrhoeaPedigree studies point to recessive inheritance (Westermarck; Moeller et al. 2002); no rate in the sources usedEnzyme treatment by a vet; avoid breeding affected lines

A DM-tested dog that carries two copies of the mutation is at risk even if it looks healthy, and DNA testing of breeding pairs can avoid producing affected puppies. Hip and elbow scores help, but they do not guarantee a sound dog.

Genome history. Scarsbrook, Frantz and colleagues (PNAS, press release 29 January 2026) sequenced nine pedigree German Shepherds from the Natural History Museum in Bern, dated 1906 to 1993. Diversity was already far below that of medieval European dogs in the early 1900s, reflecting the founding bottleneck, and fell further after the Second World War. The most recent European bottleneck was traced to 1967 and the popular sire Quanto von der Wienerau. The authors name bringing in dogs from genetically distinct lines as the most effective way to improve the breed's health.

Living with a German Shepherd

Related breedFrench Bulldog1850 to 1898 · France
Daily realityRatingWhy
ExerciseHighMore than 2 hours a day, with training and mental work (UK Kennel Club)
Training needsHighConsistent, positive training is "absolutely necessary" (SV)
GroomingMediumBrushing more than once a week (UK Kennel Club)
SheddingHighThick undercoat in both coat varieties; sheds regularly
BarkingVariesNo source used rates it
Time alonePoorA dog bred to work with people does badly left alone for long hours
ChildrenFairCan be good with early socialisation; supervise around young children
Other dogsVariesDepends on socialisation and line
Cats and small petsVariesDepends on early introduction
Flat livingPoorLarge dog with high exercise needs; a house with a garden helps
Heat toleranceVariesDense double coat; limit hard exercise in heat
Cold toleranceGoodWeather-resistant double coat
First-time ownerFairTrainable, but a big, strong dog needs socialisation skills

A great fit if you...

  • are active, patient and consistent;
  • enjoy training and can offer a job such as tracking, obedience or sport;
  • want a dog that works closely with its person;
  • can handle a large dog that sheds.

Think twice if you...

  • are away most of the day;
  • want a low-effort pet;
  • cannot invest in early socialisation;
  • are not ready for possible hip, elbow and spinal costs.

Before you get one. Ask the breeder for hip and elbow scores, a DM DNA result, eye screening, and to meet both parents. Decide between a working-line dog (more drive, flatter back) and a show-line dog. Breed rescues exist, and an adult dog's temperament is already visible. Expect a first year of puppy classes, socialisation and steady training.

Similar breeds to consider

German Shepherd fun facts

Related breedGiant Schnauzer1850 to 1923 · Germany
  • Horand's price was reportedly 200 marks, and he was stud book number 1.
  • In 1919 the UK registered 54 German Shepherds under the name Alsatian Wolf Dog. By 1926 the number was over 8,000.
  • Rin Tin Tin never won the first Academy Award for best actor, despite a popular legend. A former head of the Academy, Bruce Davis, called the story an urban legend.
  • The first guide dogs trained at The Seeing Eye were German Shepherds.

Frequently asked questions

Is an Alsatian the same as a German Shepherd?

Yes. Alsatian is the old British name, used from the First World War period until the Kennel Club allowed the original name again in 1977.

How big do German Shepherds get?

FCI: 60 to 65 cm and 30 to 40 kg for dogs, 55 to 60 cm and 22 to 32 kg for bitches.

How long do German Shepherds live?

The UK median is 10.3 years. The SV gives 10 to 12 years, and project data gives 9 to 13.

Are German Shepherds good family dogs?

They can be, with early socialisation, training and supervision around young children. They need a lot of activity and company.

Do German Shepherds shed?

Yes, regularly. Both coat varieties have a thick undercoat.

Are white German Shepherds allowed in shows?

Not under the FCI standard, which lists white as not allowed. The UK Kennel Club calls whites highly undesirable. White dogs are recognised as their own breeds, the White Shepherd and the White Swiss Shepherd Dog.

Is a German Shepherd the same as a Belgian Malinois?

No. They are sister breeds that share herding ancestry, and the Parker 2017 study finds 42.6 Mb of shared DNA. The Malinois is usually lighter in build and is a coat variety of the Belgian Shepherd.

Why are German Shepherds used by police and the military?

Stephanitz built the breed for trainability and steadiness, and police services chose it early, in Germany in the 1920s. Drive, stamina and a willingness to work with a handler matter more than scenting ability.

Read next

Sources (23)
  1. American Kennel Club, German Shepherd Dog breed page and "German Shepherd Dog History".
  2. Awano T. et al., "Genome-wide association analysis reveals a SOD1 mutation in canine degenerative myelopathy that resembles amyotrophic lateral sclerosis", Proceedings of the National Academy of Sciences, 2009.
  3. BVA and The Kennel Club, Hip Dysplasia Scheme breed-specific statistics, 2025 edition.
  4. Fédération Cynologique Internationale, Deutscher Schäferhund (German Shepherd Dog), standard no. 166 (German original dated 23 March 2010, English version 23 December 2010).
  5. German Shepherd Dog Club of America, "The History of the German Shepherd Dog" and SV programme pages.
  6. Glickman L.T. et al., "Non-dietary risk factors for gastric dilatation-volvulus in large and giant breed dogs", Journal of the American Veterinary Medical Association, 2000.
  7. Hall N.J., Glenn K., Smith D.W., Wynne C.D.L., "Performance of pugs, German shepherds, and greyhounds (Canis lupus familiaris) on an odor-discrimination task", Journal of Comparative Psychology, 2015.
  8. Holder A.L. et al., "Assessing the prevalence of the SOD1 mutation associated with degenerative myelopathy in German Shepherd dogs in the UK", Canine Genetics and Epidemiology, 2014.
  9. Humphries A., Shaheen A.F., Gómez Álvarez C.B., "Different conformations of the German shepherd dog breed affect its posture and movement", Scientific Reports, 2020.
  10. Ludwig-Maximilians-Universität München, press release on Scarsbrook et al., "A 120-y time series of genomes reveals the consequences of closed breeding in German shepherd dogs", Proceedings of the National Academy of Sciences, 2026 (press release 29 January 2026).
  11. Moeller E.M. et al., "Inheritance of pancreatic acinar atrophy in German Shepherd Dogs", American Journal of Veterinary Research, 2002.
  12. Morrill K. et al., "Ancestry-inclusive dog genomics challenges popular breed stereotypes", Science, 2022.
  13. MRCVSonline, news coverage of Crufts 2016 (16 March 2016) and of the Kennel Club breed health guide for judges (7 March 2018).
  14. O'Neill D.G., Coulson N.R., Church D.B., Brodbelt D.C., "Demography and disorders of German Shepherd Dogs under primary veterinary care in the UK", Canine Genetics and Epidemiology, 2017.
  15. Parker H.G. et al., "Genomic analyses reveal the influence of geographic origin, migration, and hybridization on modern dog breed development", Cell Reports, 2017.
  16. Polgár Z. et al., "A test of canine olfactory capacity: comparing various dog breeds and wolves in a natural detection task", PLoS ONE, 2016.
  17. Schäferhunde.de, Verein für Deutsche Schäferhunde (SV), history and breed information pages.
  18. The Seeing Eye, history, and Eustis D.H., "The Seeing Eye", The Saturday Evening Post, 5 November 1927.
  19. The Kennel Club (UK; styled Royal Kennel Club on its current website), German Shepherd Dog breed standard (updated 1 August 2025) and breed information page.
  20. Westermarck E. and colleagues, pedigree studies of exocrine pancreatic insufficiency in German Shepherd dogs.
  21. Wikipedia, "German Shepherd", "Max von Stephanitz", "Verein für Deutsche Schäferhunde", "Horand von Grafrath", "Rin Tin Tin", "Strongheart", "The Seeing Eye", "Guide dog", "Police dog", "White Shepherd", "Czechoslovakian Wolfdog" and "Pedigree Dogs Exposed" (used for dates and summaries, checked against the other sources listed).
  22. Zeng R. et al., "Breed distribution of SOD1 alleles previously associated with canine degenerative myelopathy", Journal of Veterinary Internal Medicine, 2014.
  23. Project knowledge base, breed records and Parker 2017 shared-haplotype table (this site).