Chihuahua (dog)

Chihuahua
Chihuahua1 bvdb.jpg
Origin Mexico
Traits
Height 15–25 cm (6–10 in)
Weight 1.8–2.7 kg (4–6 lb)
Coat Short-haired (smooth coat) and long-coat
Color Any color
Litter size usually 2–5
Life span 12–20
Kennel club standards
FCI standard
Dog (domestic dog)

The Chihuahua (/ɪˈwɑːwə, -wɑː, -ˈw.ə/ (About this soundlisten);[1] Spanish: chihuahueño) is one of the smallest breeds of dog,[2] and is named after the Mexican state of Chihuahua.

History

Chihuahuas remained a rarity until the early 20th century, and the American Kennel Club did not register a Chihuahua until 1904.[3] In a 1520 letter, Hernan Cortés wrote that the Aztecs raised and sold the little dogs as food.[4] Colonial records refer to small, nearly hairless dogs at the beginning of the 19th century, one of which claims 16th-century Conquistadores found them plentiful in the region later known as Chihuahua.[5]

Genetic Lineage

An analysis of DNA from the genome of domesticated dogs indicates that they entered North America from Siberia for 4,500 years and were then isolated for the next 9,000 years. After contact with Europeans, these lineages were replaced by Eurasian dogs and their local descendants. The pre-contact dogs exhibited a unique genetic signature that is now almost gone.[6] In 2020, the sequencing of ancient dog genomes indicates that in two Mexican breeds the Chihuahua retains 4% and the Xoloitzcuintli 3% pre-colonial ancestry.[7]

Appearance

Chihuahuas are the smallest breed recognized by some kennel clubs.[8]

Profile of deer-headed dog
A shorthair deer head Chihuahua
Profile of apple head dog
A shorthair apple head Chihuahua, showing pronounced stop

Current breed standards defined by registries specify an "apple-head" or "apple-dome" skull conformation.[9] Chihuahuas have large, round eyes and large, erect ears, set in a high, dramatically rounded skull.[8] The stop is well defined, forming a near 90 degree angle where the muzzle meets the skull.[10] Dogs of the older "deer" type, with a flat-topped head, more widely set eyes, larger ears, and longer, more slender legs, may still be registered.[9][10]

Breed standards for this dog do not generally specify a height; only a weight and a description of their overall proportions. Generally, the height ranges between 6 and 9 in (15 and 23 cm);[8] however, some dogs grow as tall as 30 to 38 cm (12 to 15 in). Both British and American breed standards state that a Chihuahua must not weigh more than 5.9 lb (2.7 kg) for conformation.[8]

However, the British standard also states that a weight of 4–6 lb (1.8–2.7 kg) is preferred. A clause stating, "if two dogs are equally good in type, the more diminutive one is preferred" was removed in 2009.[11] The Fédération Cynologique Internationale standard calls for dogs ideally between 1.5 and 3.0 kg (3.3 and 6.6 lbs), although smaller ones are acceptable in the show ring.[12]

Pet Chihuahuas (those bred or purchased as companions rather than show dogs) often range above these weights, even above 10 lbs, if they have large bone structures or are allowed to become overweight.[8] This does not mean that they are not purebred Chihuahuas; they just do not meet the requirements to enter a conformation show. Oversized Chihuahuas are seen in some of the best, and worst, bloodlines. Chihuahuas do not breed true for size, and puppies from the same litter can mature in drastically different sizes from one another. Also, larger breeding females are less likely to experience dystocia (obstructed labour). Many breeders try to breed Chihuahuas as small as possible, because those marketed as "teacup" or "tiny teacup" demand higher prices.[13]

Chihuahuas occur in virtually any color combination, from solid to marked or splashed.[14]

The Fédération Cynologique Internationale, which represents the major kennel clubs of 84 countries, disqualified the merle coat pattern, which appears mottled.[12] In May 2007, The Kennel Club decided not to register puppies with this coloration due to the health risks associated with the responsible gene, and in December of that year, formally amended its breed standard to disqualify merle dogs.[15]

Like many other small dogs, the Chihuahua may display above-average aggression towards people and other dogs.[16][17]

Health

Chihuahua puppy

The Chihuahua has some predisposition to several neurological diseases, among them atlantoaxial instability, ceroid lipofuscinosis, congenital deafness, congenital hydrocephalus, muscular dystrophy, necrotizing meningoencephalitis and neuroaxonal dystrophy.[18]: 3 [19] In a radiographical study of canine periodontal disease in 2001, the Chihuahua was found to have the lowest incidence of any of the six breeds studied.[20]: 206 [21]: 532 

A chihuahua with a carpal valgus deformity in the left forelimb.

Chihuahuas may suffer from patellar luxation.[22]

See also

References

  1. ^ Wells, John (April 3, 2008). Longman Pronunciation Dictionary (3rd ed.). Pearson Longman. ISBN 978-1-4058-8118-0.
  2. ^ "The 25 Smallest Dog Breeds". American Kennel Club. Retrieved January 26, 2021.
  3. ^ Coile, C. (2013). Chihuahuas: Everything about purchase, care, nutrition, behavior, and training. Hauppauge, NY: Barron’s Educational Series, p. 7: "Only in 1904 did the American Kennel Club (AKC) register its first Chihuahua; a total of five were registered that year.”
  4. ^ "Hernan Cortés: from Second Letter to Charles V, 1520". Fordham University. Retrieved March 25, 2014.
  5. ^ Pedro Baptista Pino y Juan Lopez Cancelada, Exposición sucinta y sencilla de la Provincia del Nuevo México y otros escritos. Ed. Jesus Paniagua Perez. Valladolid: Junta de Castilla / León: Universidad de León, 2007, p. 244: "even in the desert the tiny dogs could be found, hunting rats, mice, and lizards." The footnote that follows alludes to starving Conquistadores reportedly hunting and stewing the dogs (Universidad Veracruzana, Arquivo Viejo, XXVI.2711).
  6. ^ Ní Leathlobhair, Máire; et al. (July 6, 2018). "The evolutionary history of dogs in the Americas". Science. 361 (6397): 81–85. Bibcode:2018Sci...361...81N. doi:10.1126/science.aao4776. PMC 7116273. PMID 29976825. S2CID 206663458.
  7. ^ Bergström, Anders; et al. (2020). "Origins and genetic legacy of prehistoric dogs". Science. 370 (6516): 557–564. doi:10.1126/science.aba9572. PMC 7116352. PMID 33122379. S2CID 225956269.
  8. ^ a b c d e Charlotte Wilcox (April 1, 1999). "Quick Facts". The Chihuahua. Capstone. pp. 4–5. ISBN 978-0-7368-0158-4. Retrieved March 1, 2013.
  9. ^ a b Walker, Joan Hustace (2006). The Everything Chihuahua Book: A Complete Guide to Raising, Training, And Caring for Your Chihuahua. Adams Media. pp. 16–18. ISBN 9781440523687. Retrieved June 15, 2019.
  10. ^ a b "Official Standard of the Chihuahua" (PDF). Retrieved November 12, 2019.
  11. ^ "The Kennel Club". thekennelclub.org.uk. Archived from the original on October 30, 2017. Retrieved October 17, 2013.
  12. ^ a b "Chihuahua standard" (PDF). Fédération Cynologique Internationale. July 28, 2009. Retrieved October 25, 2011.
  13. ^ Segovia, Stacey Smith (March 21, 2004). "Runt of the litter". The Leaf Chronicle. ProQuest 441596979.
  14. ^ American Kennel Club Chihuahua page, retrieved on July 29, 2007.
  15. ^ "Kennel Club breed standard". Thekennelclub.org.uk. May 15, 2006. Archived from the original on January 3, 2009. Retrieved August 14, 2009.
  16. ^ Deborah L. Duffy, Yuying Hsu, James A. Serpell (2008). Breed differences in canine aggression. Applied Animal Behaviour Science. 114 (3–4, December 2008): 441–460. doi:10.1016/j.applanim.2008.04.006. (subscription required).
  17. ^ Paul D. McGreevy, Dana Georgevsky, Johanna Carrasco, Michael Valenzuela, Deborah L. Duffy, James A. Serpell (December 2013). Dog Behavior Co-Varies with Height, Bodyweight and Skull Shape. PlosOne. doi:10.1371/journal.pone.0080529.
  18. ^ Curtis W. Dewey, Ronaldo C. Da Costa (2016). Signalment and History: The First Considerations. In: Curtis W. Dewey, Ronaldo C. Da Costa (2016). Practical Guide to Canine and Feline Neurology, third edition. Ames, Iowa; Chichester, West Sussex; Oxford: Wiley Blackwell. ISBN 9781119946113, pages 1–8.
  19. ^ Chihuahua (long and smooth coat): Hydrocephalus. Genetic Welfare Problems of Companion Animals. Wheathampstead, Hertfordshire: The International Animal Welfare Science Society/Universities Federation for Animal Welfare. Accessed February 2021.
  20. ^ V. Butković, M. Šimpraga, M. Šehić, et al. (2001) Dental diseases of dogs: a retrospective study of radiological data. Acta Veterinaria Brno. 70: 203–208.
  21. ^ C. Wallis, L. J. Holcombe (2020). A review of the frequency and impact of periodontal disease in dogs. Journal of Small Animal Practice. 61: 529–540. doi:10.1111/jsap.13218.
  22. ^ https://akcchf.org/educational-resources/library/articles/articles/chihuahuaupdate0410.pdf

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