The Chihuahua (or ) is a Mexican
breed
A breed is a specific group of breedable domestic animals having homogeneous appearance (phenotype), homogeneous behavior, and/or other characteristics that distinguish it from other organisms of the same species. In literature, there exist seve ...
of
toy dog. It is named for the Mexican state of
Chihuahua and is one of the smallest
dog breed
A dog breed is a particular type of dog that was purposefully bred by humans to perform specific tasks, such as herding, hunting, and guarding. Dogs are the most variable mammal on Earth, with artificial selection producing upward of 360 globall ...
s in the world. It is usually kept as a
companion animal.
History
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.
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).
Other studies have suggested that the pre-colonial ancestry of the Chihuahua may be as high as 70%.
Colonial records refer to small, nearly hairless dogs at the beginning of the nineteenth century; one claims that sixteenth-century
conquistadores
Conquistadors (, ) or conquistadores (; ; ) were Spanish Empire, Spanish and Portuguese Empire, Portuguese colonizers who explored, traded with and colonized parts of the Americas, Africa, Oceania and Asia during the Age of Discovery. Sailing ...
found them plentiful in the region later known as Chihuahua. In a letter written in 1520,
Hernan Cortés wrote that the
Aztecs
The Aztecs ( ) were a Mesoamerican civilization that flourished in central Mexico in the post-classic period from 1300 to 1521. The Aztec people included different ethnic groups of central Mexico, particularly those groups who spoke the ...
raised and sold
little dogs as food.
The
American Kennel Club
The American Kennel Club (AKC) is a 501(c)(4) nonprofit breed registry, registry of purebred dog pedigree (animal), pedigrees in the United States. In addition to maintaining its pedigree registry, this kennel club also promotes and sanctions eve ...
first registered a Chihuahua in 1904, Midget, owned by H. Raynor of Texas.
Characteristics
Chihuahua breed standards specify an "apple-head" or "apple-dome" skull conformation.
Chihuahuas occur in virtually any color combination, from solid to marked or splashed.
[American Kennel Club Chihuahua page](_blank)
retrieved on July 29, 2007. Apple-dome Chihuahuas have large, round eyes and large, erect ears, set in a high, dramatically rounded skull.
The stop is well defined, forming a near-90-degree angle where the muzzle meets the skull.
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.
Breed standard
In animal husbandry or animal fancy, a breed standard is a description of the characteristics of a hypothetical or ideal example of a breed. The description may include phenotype, physical or morphology (biology), morphological detail, genotype, g ...
s for this dog do not generally specify a height; only a weight and a description of their overall proportions. Generally, the height ranges between ;
some dogs grow to .
The
Fédération Cynologique Internationale
The (; FCI; ) is the largest international federation of national kennel clubs and purebred registries. The FCI is based in Thuin, Belgium and has 98 members and contract partners (one from each country).
History
The FCI was founded in 1911 un ...
standard calls for dogs ideally between ; those outside the range are disqualified from exhibition. The American breed standard sets a maximum weight of for showing.
In the British standard a weight of is preferred – the clause "if two dogs are equally good in type, the more diminutive one is preferred" was removed in 2009.
Pet Chihuahuas (those bred or purchased as companions rather than as show dogs) often range above these weights, even above , if they have large bone structures or are allowed to become overweight.
This does not mean that they are not purebred Chihuahuas; they just do not meet the requirements to enter a
conformation show
A dog show is an animal show; it is an event where dogs are exhibited. A conformation show, also referred to as a '' breed show'', is a kind of dog show in which a judge, familiar with a specific dog breed, evaluates individual purebred dogs ...
. 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.
The international standard disallows the
merle coat pattern, which appears mottled. 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.
Like many other small dogs, the Chihuahua may display above-average aggression toward people and other dogs.
Health
The Chihuahua has some
genetic predisposition
Genetic predisposition refers to a genetic characteristic which influences the possible phenotypic development of an individual organism within a species or population under the influence of environmental conditions. The term genetic susceptibil ...
to several
neurological diseases, among them
atlantoaxial instability,
ceroid lipofuscinosis,
congenital deafness,
congenital hydrocephalus,
muscular dystrophy
Muscular dystrophies (MD) are a genetically and clinically heterogeneous group of rare neuromuscular diseases that cause progressive weakness and breakdown of skeletal muscles over time. The disorders differ as to which muscles are primarily affe ...
,
necrotizing meningoencephalitis, and
neuroaxonal dystrophy; it has a mild predisposition to
congenital heart disease
A congenital heart defect (CHD), also known as a congenital heart anomaly, congenital cardiovascular malformation, and congenital heart disease, is a defect in the structure of the heart or great vessels that is present at birth. A congenital he ...
. In a
radiographical study of canine
periodontal disease
Periodontal disease, also known as gum disease, is a set of inflammatory conditions affecting the tissues surrounding the teeth. In its early stage, called gingivitis, the gums become swollen and red and may bleed. It is considered the main c ...
in 2001, the Chihuahua was found to have the lowest incidence of the six breeds studied. The predisposition to
medial patellar luxation is believed to be significant.
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. 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. 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. A 2024 Italian study found a life expectancy of 8.5 years for the breed compared to 10 years overall.
A UK study found the Chihuahua bitch to be more than 10.4 times more likely to experience
dystocia.
See also
*
List of dog breeds
This list of dog breeds includes both Neontology#Extant taxa versus extinct taxa, extant and extinct dog breeds, Designer breed, varieties and dog type, types. A research article on dog genomics published in Science/AAAS defines modern dog breeds ...
*
Ren Hoek from Nickelodeon's ''
The Ren & Stimpy Show
''The Ren & Stimpy Show'', commonly referred to as simply ''Ren & Stimpy'', is an American animated Comedy film, comedy television series created by John Kricfalusi for Nickelodeon. The series follows the misadventures of Ren Höek, an emotion ...
''
*
Techichi
* ''
Beverly Hills Chihuahua''
*
Chihuahua (state)
Chihuahua, officially the Free and Sovereign State of Chihuahua, is one of the 31 states which, along with Mexico City, comprise the Political divisions of Mexico, 32 federal entities of Mexico. It is located in the northwestern part of Mexico a ...
Notes
References
{{DEFAULTSORT:Chihuahua
Companion dogs
Dog breeds originating from Indigenous Americans
Dog breeds originating in Mexico
FCI breeds
Mexican folklore
Toy dogs