Chihuahua Mix: Size, Coat, Temperament and What DNA Shows

A Chihuahua mix is any dog with Chihuahua ancestry, from a deliberate first cross such as a Chihuahua and Dachshund to a shelter dog with a Chihuahua somewhere in its family tree. It's one of the most common ancestries in mixed-breed dogs: in a DNA study of 919 shelter dogs, Chihuahua was one of the two most common breeds at both shelters studied. Because the Chihuahua is the smallest breed, the other breeds in the mix decide most of the size, and a DNA test can estimate what they are.

The Chihuahua side at a glance

How common is Chihuahua ancestry?

Very. A study that DNA-tested 919 dogs at shelters in Phoenix and San Diego found Chihuahua in 24% of the dogs in Phoenix, tied with the American Staffordshire Terrier as the most common breed there, and in 17.8% in San Diego, second only to the American Staffordshire Terrier. In the dogs that had it, Chihuahua made up about 38 to 40% of their ancestry on average, a little over three of their eight great-grandparents.

The same study found 12 dogs whose two parents were purebreds of different breeds, and half of them had a Chihuahua parent: three Chihuahua and Rat Terrier crosses, and one each with a Russell Terrier, a Labrador Retriever and a Poodle. Those were U.S. shelters, and Canadian shelter dogs may differ, but the pattern is a reminder of how common Chihuahua ancestry is in shelter mixes. Our guide to DNA testing a rescue dog covers what else shelter studies found.

Common Chihuahua crosses

Many Chihuahua mixes are deliberate crosses with their own nicknames:

A nickname only tells you the intended parents. Each parent breed brings its own genetics: a Dachshund parent, for example, can pass on the gene variant behind the breed's short legs, which a 2009 study linked to at least 19 short-legged breeds. A 2024 study of UK dogs named the Jack Chi, alongside the Labradoodle, as an example of a designer crossbreed.

How big will a Chihuahua mix get?

The Chihuahua is tiny, at 0.5 to 3 kg according to the Canadian Kennel Club, so the other side of the family sets most of a mix's size. A Chihuahua crossed with another toy breed usually stays small, while a cross with a bigger breed can end up anywhere between the two parents. A mix often lands somewhere between its parents' sizes, though not necessarily in the middle, because size depends on which size genes each puppy inherits.

Small size is strongly genetic. A 2007 study found one version of the growth gene IGF1 is common to all small breeds and nearly absent from giant ones. Our guide to how big a mixed-breed puppy will get explains how to combine the parents' sizes, growth checks and genetics.

Coat and colour

Chihuahuas come in two coats. The smooth coat is soft, close and glossy, and the long coat is soft and flat or slightly curly, with fringed ears and a plumed tail. The CKC notes the long coat is thought to have come from crossing short-coated Chihuahuas with other toy breeds. Long hair in dogs usually comes from recessive variants of the FGF5 gene, so two smooth-coated dogs that each carry one copy can have a long-coated puppy. Our guide to long coats explains how it works.

For colour, the Chihuahua standard allows almost anything, solid, marked or splashed, except merle. In a mix, the other parent can add colours and patterns of its own. Merle is the one to watch: two merle parents can have double merle puppies, which our guide to merle dogs explains. Our coat colour hub covers the genes behind the rest.

Temperament

The CKC describes the Chihuahua as alert and spirited, "personality in a small package", a dog that may become very attached to its owner and makes a fine little watchdog. A Chihuahua mix may share some of that, mixed with tendencies from its other breeds. Breed is a loose guide to any one dog, though: a 2022 study of more than 18,000 dogs found breed explains only about 9% of behavioural differences between individual dogs.

Reading a Chihuahua result in a DNA report

The PuppyGenes breed ancestry section estimates a dog's breed mix as percentages, including any ancestry that couldn't be resolved. A few pointers:

• A dog doesn't have to be small to carry Chihuahua. Size depends on which genes each puppy inherits from each side.
• Around 50% Chihuahua suggests one Chihuahua parent, and around 25% a Chihuahua grandparent, though real results rarely land on exact fractions. Our guide to breed percentages explains why.
• Closely related breeds are harder to separate, as are small contributions, especially where reference data are limited.
• If the result surprises you, our guide to why DNA results don't match looks covers the usual reasons.

If you're weighing a test, our guides to whether dog DNA tests are legit and dog DNA testing in Canada cover what to check before you buy.