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Chihuahua (dog breed)

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"Chihuahuas" redirects here. For the baseball team, see El Paso Chihuahuas.

Chihuahua
Other namesChihuahueño
OriginMexico
Traits
Height
8–23 cm (3–9 in)[2]: 276 
Weight
1–3 kg (2–7 lb)[1]
Coat short-haired (smooth) or long-haired
Color all colors admitted, except merle[3][4]
Kennel club standards
Fédération Cynologique Internationale standard
Dog (domestic dog)

The Chihuahua[a] (or Spanish: Chihuahueño) is a Mexican breed of toy dog. It is named for the Mexican state of Chihuahua and is the smallest dog breed in the world.[5] It is usually kept as a companion animal.

History

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DNA studies suggest that native American dogs entered North America from Siberia roughly 10,000 years ago, and were then isolated for some 9,000 years until the arrival of the first Europeans; these pre-contact dogs exhibited a unique genetic signature that is now almost gone.[6] A study based on sequencing of ancient dog genomes, published in 2020, suggests that this pre-colonial ancestry survives in two Mexican breeds, to the extent of about 4% in the Chihuahua (and some 3% in the Xoloitzcuintli).[7]

Colonial records refer to small, nearly hairless dogs at the beginning of the nineteenth century; one claims that sixteenth-century conquistadores found them plentiful in the region later known as Chihuahua.[8] In a letter written in 1520, Hernan Cortés wrote that the Aztecs raised and sold little dogs as food.[9]

The American Kennel Club first registered a Chihuahua in 1904, Midget, owned by H. Raynor of Texas.[10][11]

Characteristics

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

Chihuahua breed standards specify an "apple-head" or "apple-dome" skull conformation.[12] Chihuahuas occur in virtually any color combination, from solid to marked or splashed.[13] Apple-dome Chihuahuas have large, round eyes and large, erect ears, set in a high, dramatically rounded skull.[14] The stop is well defined, forming a near-90-degree angle where the muzzle meets the skull.[3] 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, but the deer head is not considered a separate type in competition and a deer-head dog's digression from the breed standard is considered a fault.[12][3]

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 15 and 23 cm (6 and 9 in);[14] some dogs grow to 30 to 38 cm (12 to 15 in).[citation needed]

The Fédération Cynologique Internationale standard calls for dogs ideally between 1.5 and 2.5 kg (3.3 and 5.5 lb); those outside the range 1.0–3.0 kg (2.2–6.6 lb) are disqualified from exhibition.[1] The American breed standard sets a maximum weight of 2.7 kg (5.9 lb) for showing.[14] In the British standard a weight of 1.8–2.7 kg (4–6 lb) is preferred – the clause "if two dogs are equally good in type, the more diminutive one is preferred" was removed in 2009.[15]

Pet Chihuahuas (those bred or purchased as companions rather than as show dogs) often range above these weights, even above 4.5 kg (10 lb), if they have large bone structures or are allowed to become overweight.[14] 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 labor). Many breeders try to breed Chihuahuas to be as small as possible, because those marketed as "teacup" or "tiny teacup" demand higher prices.[16]

The international standard disallows the merle coat pattern, which appears mottled.[1] In 2007 The Kennel Club of Great Britain amended its breed standard to disqualify merle dogs because of the health risks associated with the underlying gene.[17]

Like many other small dogs, the Chihuahua may display above-average aggression toward people and other dogs.[18][19]

Health

[edit]

The Chihuahua has some genetic predisposition to several neurological diseases, among them atlantoaxial instability, ceroid lipofuscinosis, congenital deafness, congenital hydrocephalus, muscular dystrophy, necrotizing meningoencephalitis, and neuroaxonal dystrophy;[20]: 3 [21] it has a mild predisposition to congenital heart disease.[22]: 478  In a radiographical study of canine periodontal disease in 2001, the Chihuahua was found to have the lowest incidence of the six breeds studied.[23]: 206 [24]: 532  The predisposition to medial patellar luxation is believed to be significant.[25]: 46 

A 2018 study in Japan of pet cemetery data found the Chihuahua to have an average life expectancy of 11.8 years compared to 15.1 for crossbreeds and 13.7 overall.[26] A 2022 UK study on life expectancy of dog breeds based on veterinary data showed the average life expectancy to be 7.91 for the breed compared to 11.82 years for crossbreeds.[27][b] A 2024 UK study found a life expectancy of 11.8 years for the breed compared to an average of 12.7 for purebreeds and 12 for crossbreeds.[28] A 2024 Italian study found a life expectancy of 8.5 years for the breed compared to 10 years overall.[29]

A UK study found the Chihuahua bitch to be more than 10.4 times more likely to experience dystocia.[30]

See also

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Notes

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  1. ^ English: /tʃɪˈwɑːwə, -wɑː, -ˈwaʊ.ə/ ⓘ; Spanish: [tʃiˈwawa].[31]
  2. ^ The Japanese study reviewed cemetery data which is unlikely to have any records of still-births and altricial deaths whilst a veterinary clinic likely would have data on these.

References

[edit]
  1. ^ a b c FCI-Standard N° 218: Chihuahueño (Chihuahua). Fédération Cynologique Internationale. Accessed October 2024.
  2. ^ Kim Dennis-Bryan (2020 [2012])). The Complete Dog Breed Book, second edition. London: Dorling Kindersley. ISBN 9780241412732.
  3. ^ a b c "Official Standard of the Chihuahua" (PDF). Retrieved November 12, 2019.
  4. ^ "CHIHUAHUEÑO" (PDF). fci.be. The Fédération Cynologique Internationale. October 4, 2019. p. 5. Retrieved June 19, 2024. Colour: All colours in all possible shades and combinations are admitted, except merle colour.
  5. ^ "The 25 Smallest Dog Breeds". American Kennel Club. Retrieved January 26, 2021.
  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. ^ 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).
  9. ^ "Hernan Cortés: from Second Letter to Charles V, 1520". Fordham University. Archived from the original on August 23, 2014. Retrieved March 25, 2014.
  10. ^ 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."
  11. ^ "Chihuahua History: From Aztec Treasure to Popular Companion". American Kennel Club. January 6, 2022. Retrieved September 28, 2022.
  12. ^ 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.
  13. ^ American Kennel Club Chihuahua page, retrieved on July 29, 2007.
  14. ^ a b c d Charlotte Wilcox (April 1, 1999). "Quick Facts". The Chihuahua. Capstone. pp. 4–5. ISBN 978-0-7368-0158-4. Retrieved March 1, 2013.
  15. ^ "The Kennel Club". thekennelclub.org.uk. Archived from the original on October 30, 2017. Retrieved October 17, 2013.
  16. ^ Segovia, Stacey Smith (March 21, 2004). "Runt of the litter". The Leaf Chronicle. ProQuest 441596979.
  17. ^ "Kennel Club breed standard". Thekennelclub.org.uk. May 15, 2006. Archived from the original on January 3, 2009. Retrieved August 14, 2009.
  18. ^ 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).
  19. ^ 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.
  20. ^ 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.
  21. ^ 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.
  22. ^ P. Oliveira, O. Domenech, J. Silva, S. Vannini, R. Bussadori, C. Bussadori (2011). Retrospective Review of Congenital Heart Disease in 976 Dogs. Journal of Veterinary Internal Medicine. 25: 477-483. doi:10.1111/j.1939-1676.2011.0711.x.
  23. ^ 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.
  24. ^ 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.
  25. ^ Alex Gough, Alison Thomas (2004). Breed Predispositions to Disease in Dogs and Cats. Oxford: Blackwell Publishing. ISBN 9781405107488.
  26. ^ INOUE, Mai; KWAN, Nigel C. L.; SUGIURA, Katsuaki (2018). "Estimating the life expectancy of companion dogs in Japan using pet cemetery data". Journal of Veterinary Medical Science. 80 (7). Japanese Society of Veterinary Science: 1153–1158. doi:10.1292/jvms.17-0384. ISSN 0916-7250. PMC 6068313. PMID 29798968.
  27. ^ Teng, Kendy Tzu-yun; Brodbelt, Dave C.; Pegram, Camilla; Church, David B.; O’Neill, Dan G. (April 28, 2022). "Life tables of annual life expectancy and mortality for companion dogs in the United Kingdom". Scientific Reports. 12 (1). Springer Science and Business Media LLC: 6415. Bibcode:2022NatSR..12.6415T. doi:10.1038/s41598-022-10341-6. ISSN 2045-2322. PMC 9050668. PMID 35484374.
  28. ^ McMillan, Kirsten M.; Bielby, Jon; Williams, Carys L.; Upjohn, Melissa M.; Casey, Rachel A.; Christley, Robert M. (February 1, 2024). "Longevity of companion dog breeds: those at risk from early death". Scientific Reports. 14 (1). Springer Science and Business Media LLC. doi:10.1038/s41598-023-50458-w. ISSN 2045-2322. PMC 10834484.
  29. ^ Roccaro, Mariana; Salini, Romolo; Pietra, Marco; Sgorbini, Micaela; Gori, Eleonora; Dondi, Maurizio; Crisi, Paolo E.; Conte, Annamaria; Dalla Villa, Paolo; Podaliri, Michele; Ciaramella, Paolo; Di Palma, Cristina; Passantino, Annamaria; Porciello, Francesco; Gianella, Paola; Guglielmini, Carlo; Alborali, Giovanni L.; Rota Nodari, Sara; Sabatelli, Sonia; Peli, Angelo (2024). "Factors related to longevity and mortality of dogs in Italy". Preventive Veterinary Medicine. 225: 106155. doi:10.1016/j.prevetmed.2024.106155. hdl:11585/961937. ISSN 0167-5877.
  30. ^ Packer, Rowena. "New study reveals flat faced dogs have the highest risk when giving birth". Royal Veterinary College. University of London. Retrieved March 13, 2024.
  31. ^ Wells, John (April 3, 2008). Longman Pronunciation Dictionary (3rd ed.). Pearson Longman. ISBN 978-1-4058-8118-0.
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