Horses with a spotted coat pattern are often referred to as either “calico” or “pinto”, depending on the breed. The term “calico” is most commonly used to describe American Paint Horses, which have large patches of white and another color. “Pinto” more often refers to a light horse breed like an American Pinto or Pony of the Americas with white spotting. However, there is some overlap between the terms and they are sometimes used interchangeably. The spotting patterns and genetics in horses are complex, which leads to the varied terminology. Ultimately, “calico” and “pinto” are descriptive terms for the colorful spotted coat pattern rather than a specific breed.
Origin of “Calico” and “Pinto”
The term “calico” originated from a type of cotton fabric called calico that was woven or printed with a spotted or patchwork pattern. This inspired the descriptor for spotted horses. “Pinto” has Spanish roots relating to the pinto bean, which has a speckled appearance similar to some spotted horses. Over time, horse enthusiasts began associating these terms with specific breeds or looks. “Pinto” became affiliated with pintos derived from Iberian bloodlines and exhibiting white spotting all over the body. “Calico” was more often used for American stock horse breeds like Quarter Horses with patches of white over the rear and larger spots. However, there are still pintos with a calico-like pattern and calicos that could be described as pinto. The differentiation is not consistent.
Coat Patterns in Calico and Pinto Horses
Both calico and pinto horses exhibit one of several recognized coat patterns that produce white spotting:
Tobiano
- White patches are regular and distinct across the body
- Head is usually dark with minimal white markings
- Legs are typically white high up on the legs
- White spots usually cross the topline between the withers and tail
Overo
- White patches are irregular with jagged edges
- High amount of white on the head
- Dark legs
- White rarely crosses the back between the withers and tail
Sabino
- Irregular spotting like overo
- White markings on legs often extend high up
- Face is often white
- Roaning patches in addition to white spots
Splashed white
- Bottom heavy white patches
- White facial markings like a blaze
- White on legs
Dominant white
- White coat with pigmented skin
- Blue eyes
These patterns can combine to create an even more unique coat. Pinto registries categorize horses into different pinto patterns like tobiano, overo, and tovero (tobiano + overo). Calico stock horse registries are more concerned with the horse’s pedigree than specifying the patterning.
Genetics Behind Calico and Pinto Spotting
The white spotting patterns arise from complex interactions between multiple genes. Some key genes include:
KIT gene
The KIT gene is responsible for producing the KIT protein, which plays a role in melanocyte migration and survival during development. Mutations in KIT lead to a lack of melanocytes in patches, resulting in white spots. These mutations account for tobiano, sabino, and dominant white patterns.
EDNRB and EDN3
The EDNRB gene encodes a receptor for endothelin 3 (EDN3) which binds endothelin 3 (a protein signal). This interaction is important for neural crest cell migration and melanocyte development. Mutations in EDNRB or EDN3 disrupt proper melanocyte migration and result in spotting like overo and sabino patterns.
PAX3
The PAX3 gene is involved in neural crest development. Mutations in PAX3 that disrupt melanocyte formation can cause white spotting. It interacts with the MITF gene which controls melanin production.
Other
Other genes tied to white spotting include ASIP, TRPM1, MITF, RFWD3, and more. Research is ongoing to fully uncover the genetics underlying pinto and calico coats.
Breeds with Calico Patterns
American Paint Horse
The American Paint Horse is the most common calico spotted breed. To be registered as a Paint, the horse must have color requirements of at least one large patch of white plus darker pigmentation. The breed started from colored stock horses like Quarter Horses and Thoroughbreds. Common coat patterns include tobiano, overo, tovero, and solid with white markings.
| Coat pattern | Description |
|---|---|
| Tobiano | Regular, distinct white patches with pigmented head |
| Overo | Irregular white spotting with high white on head |
| Tovero | Mix of dark and white patches |
| Solid | Dark body with minimal white markings |
Quarter Horse
Quarter Horses with pinto coloring can be double registered as an American Paint Horse. Other organizations like the American Quarter Horse Association only require some white markings to be registered as a solid-colored Quarter Horse. So both breeds can produce calico patterns.
Pony of the Americas
The Pony of the Americas breed was developed from crossing Appaloosa and Shetland ponies and selecting for the spotted pattern. They exhibit pinto patterns like tobiano, sabino, overo, and splashed white.
Breeds with Pinto Patterns
American Pinto Horse
The Pinto Horse Association recognizes both horses and ponies with pinto coloring. Unlike Paints, the amount of white is not specified for registration as long as some pinto white spotting is present. Common patterns include tobiano, sabino, overo, splashed white, and various combinations.
Colorado Ranger
The Colorado Ranger is a horse breed with Spanish colonial roots that often exhibits pinto spotting patterns. It has an athletic stock horse build. The white spotting comes from sabino genetics.
British Spotted Pony
This pony breed from Great Britain features white spotting. Pinto patterns like tobiano and overo are common. They are used for both riding and driving.
Unique Calico and Pinto Horses
Some distinctive calico or pinto horses include:
Medicine Hat Paint
Medicine hat refers to American Paint Horses that are mostly white except for a patch of color over the ears and forehead, resembling a Native American medicine hat. This striking look arises from the sabino pattern. Medicine hat paints are especially eye-catching.
Shield Marking Pinto
Pintos with a dark “shield” shape on their forehead are popular. The rest of the body has white patches. It comes from the sabino pattern and gives the horse a bold look.
Leopard Appaloosa
Appaloosas with the leopard complex coat pattern have white spotting overlaid with dark spots, resembling a leopard. It is an uncommon and highly desired calico-like pattern.
Few Spot Leopard
Few spot leopards have very sparse dark spots over mostly white. They almost appear fully white. It is an extremely rare calico form seen in Appaloosas.
Summary
In summary, calico and pinto are terms used to describe horses with white spotting patterns like tobiano, overo, and sabino. Breeds known for pinto coloring include the American Paint Horse, American Pinto, Pony of the Americas, Colorado Ranger, and British Spotted Pony among others. While “pinto” often refers to pintos of Spanish ancestry and “calico” to stock horses, there is overlap between the terms. Genetically the white spotting arises from mutations affecting melanocyte development and migration. Calico and pinto coat patterns provide visually striking and unique looks. Beyond color, these breeds are known for excellent temperaments and athletic versatility.
