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What breed of horse was Seabiscuit?

Seabiscuit was one of the most famous racehorses in history. His underdog story of going from an overlooked and undersized horse to a record-breaking champion captivated the nation during the Great Depression. But what exactly was the breed of this iconic racehorse?

Seabiscuit’s Origins

Seabiscuit was foaled in 1933. He was sired by Hard Tack, a successful racehorse who was known for his stamina and durability on the racetrack. Hard Tack was bred by the legendary Wheatley Stable in Kentucky. Seabiscuit’s dam was Swing On, a moderately successful racehorse who produced several other winners. Swing On was descended from the renowned sire Sweep, who was known for passing on his speed and agility to his offspring.

So what does this parentage tell us about Seabiscuit’s breed? Hard Tack and Swing On were both thoroughbreds, as were their ancestors further back in their pedigrees. This means that Seabiscuit was a thoroughbred through and through.

Thoroughbred Origins and Characteristics

The thoroughbred breed originated in 17th and 18th century England through the breeding of Arabian, Turk, and Barb horses with native English mares. This strategic breeding aimed to create an athletic horse ideal for racing at distances of around 1-2 miles. Thoroughbreds trace their lineage to one of three foundation stallions – the Byerley Turk, the Darley Arabian, and the Godolphin Arabian.

Over centuries of selective breeding, thoroughbreds have become known for the following characteristics:

  • Athletic build with long legs, muscular shoulders, deep chest, and powerful hindquarters
  • Energetic temperament and competitive spirit
  • Ability to run at high speeds over medium distances
  • Courage, intelligence, and willingness to work hard

In modern times, thoroughbreds remain the breed of choice for horse racing across the world. Their perfect combination of speed, stamina, agility, and competitive drive makes them ideally suited for racing at the elite level.

Seabiscuit’s Thoroughbred Traits

Although undersized, Seabiscuit exhibited many of the typical traits of his thoroughbred lineage:

  • Lean and athletic build, allowing efficient movement
  • Tremendous courage and competitiveness on the racetrack
  • Ability to accelerate rapidly and run at high sustained speeds
  • Eagerness to perform and please his rider
  • Remarkable agility at changing pace and direction during races

Seabiscuit stood at just 15 hands tall, which is considerably smaller than most racehorses. But he used his compact and muscular frame to his advantage, outpacing opponents with his nimble footwork and acceleration.

Seabiscuit’s Racing Career

Despite his thoroughbred pedigree, Seabiscuit was initially overlooked as a racehorse due to his small stature. He ran a total of 35 times as a two and three-year old, winning just 5 races.

At age four, however, Seabiscuit began to thrive under the guidance of his new trainer Tom Smith and jockey Red Pollard. In 1936, he won 11 of 15 starts, set track records, and emerged as one of the top handicap horses in the country.

The following year, Seabiscuit captivated the nation with marquee wins over Triple Crown winner War Admiral and the elite east coast horse War Relic. In 1938, Seabiscuit won 11 of 15 starts and decisively beat War Admiral in a legendary one-on-one match race at Pimlico racetrack.

Year Starts Wins Earnings
1936 15 11 $168,580
1937 15 11 $156,065
1938 15 11 $437,730

Over his exceptional four year racing career, Seabiscuit won 33 of 89 starts and set 16 track records at 8 different tracks. He defeated the nation’s top horses over long distances and demonstrated the courage and competitive fire typical of thoroughbreds.

Seabiscuit’s Lasting Legacy

Though undersized, Seabiscuit became one of history’s greatest racehorses through the determined spirit embodied by his thoroughbred pedigree. His rags to riches story and dashing racing style made him one of the most popular horses of the 20th century. Seabiscuit continues to be remembered and celebrated as a tenacious racehorse who overcame all odds to achieve championship glory.


In summary, Seabiscuit was a thoroughbred racehorse who overcame his small size through the incredible speed, stamina, and courage passed down from his thoroughbred lineage. His damsire Hard Tack and grandsire Sweep were both top thoroughbred runners who endowed Seabiscuit with the athleticism to excel on the racetrack. Under the guidance of his team, Seabiscuit utilized his thoroughbred talents to defeat the nation’s best racehorses and thrill fans with his underdog success. Though compact, Seabiscuit had all the traits of a champion thoroughbred – the breed that allowed him to run into racing immortality.