About the Thoroughbred

The ancestry of the Thoroughbred can be traced back to three foundation sires – the Darley Arabian, the Godolphin Arabian and the Byerly Turk. These horses were named for their owners – Thomas Darley, Lord Godophin and Captain Robert Byerly – who brought the stallions from the Middle East to England in the 17th century, where they were bred to the native horses. The result was a horse that could carry weight at sustained speed over extended distances.

Thoroughbred horse racing has a colorful and storied past, having been introduced in the American colonies before the Revolutionary War. Today The Jockey Club, formed in 1894 as the breed registry for all Thoroughbreds in North America, registers approximately 23,000 foals annually. It also maintains the American Stud Book, first published in 1873.

The Thoroughbred is considered to be one of the most athletic horse breeds on earth, capable of running and jumping at high speed for very long distances. See what it’s like to be a jump jockey riding along in a race at the Queen’s Cup.

All Thoroughbreds in the Northern Hemisphere celebrate their birthday on January 1. A newborn is known as a foal until it is weaned from its mother in the fall, at which time it becomes a weanling. On the following New Year’s Day, regardless of its foaling date, it turns 1 and is known as a yearling. On its second birthday, it is eligible to race.

Males are known as colts until they turn five, after which they become horses. Females are fillies until their fifth birthday, when they become mares. The parents of a foal are the sire (father) and dam (mother). The sons and daughters of a stallion are his progeny or get, while those of the dam are her produce.

It’s all in a Name

The Jockey Club oversees the naming of all Thoroughbred horses in the United States. Owners submit proposed names to The Jockey Club for approval. A number of restrictions govern the naming process. For instance, names may not be longer than 18 characters, including punctuation and spaces; and the names of certain famous horses, such as Secretariat, cannot be used again.

A Coat of Many Colors

Thoroughbreds come in a variety of colors. Fans may be disappointed to learn that very few are black. Grey and roan are also uncommon, while white is extremely rare. Nearly 90 percent of all Thoroughbreds registered with The Jockey Club are a variation of brown – either bay or dark bay or brown. The other official colors are chestnut, black, grey, roan, and white. Secretariat, a beautiful chestnut, had near perfect thoroughbred conformation whose heart was nearly twice as large as the average thoroughbred his size and weight.

Here’s how The Jockey Club differentiates
among the less obvious colors


The coat varies from a yellow-tan to a bright auburn, and is distinguished by a black mane, tail and legs.


The coat, mane, tail and legs range from a red-yellow to a golden-yellow.

Dark Bay or Brown

The coat varies from tan to dark brown, with the mane, tail and legs being black.


A grey’s coat is a mix of black and white hairs, and the legs, mane and tail are black or grey. A roan is a mix of red and white hairs, with the legs, mane and tail being black, chestnut or roan