Weanling, yearlings, juveniles: Exploring and explaining racehorse ages

December 8th, 2021

Weanlings, yearlings, juveniles, sophomores—in the sport of horse racing, there are many terms to describe horses of different ages.

Since the lingo is somewhat specific (and not necessarily intuitive), let’s explore and explain the five main categories of racehorse ages:


The term weanling describes a young horse, not yet one year old, that has been separated from its mother. Such a horse is said to have been “weaned” from its mother.

Weanlings are far too young to race, or even enter early training, but they’re commonly sold at North American Thoroughbred auctions. According to Bloodhorse.com, in 2019, 1,666 weanlings were offered for sale, with 1,195 selling for an aggregate total of $71,236,078.


A yearling refers to a horse that has celebrated its first birthday; it’s one year old, hence the term “yearling.” But there’s an important catch—for recordkeeping and race eligibility purposes, all Thoroughbreds age up by one year on Jan. 1 (if born on Northern Hemisphere time) or Aug. 1 (if born on Southern Hemisphere time). This means a Northern Hemisphere foal born on May 1 will technically become a yearling four months before its actual birthdate. These not-quite-yearlings are sometimes referred to as “short yearlings.”

While yearlings are not old enough to race, they’re widely sold at auctions, sometimes for million-dollar price tags. In 2019, 9,378 yearlings were offered for sale in North America, with 7,063 changing hands for a grand total of $551,422,022.

Two-year-old (“juvenile”)

Once a Thoroughbred turns two years old, it’s old enough to race. In North America, “juvenile” racing typically begins in the spring with short sprints of 4 1/2 furlongs or so. Race distances gradually increase as the year goes on, culminating with two-turn route races over 1 1/16 miles or 1 1/8 miles. Because juveniles aren’t yet mature racehorses, they compete almost exclusively against each other—they’re not yet fast enough to compete against older horses, except perhaps in short sprints.

Juveniles are often sold at auction as “two-year-olds in training,” which refers to unraced two-year-olds developed to the point where they can sprint a furlong or two to show potential buyers their stride and speed. In 2019, the peak season for two-year-olds in training sales (spanning March 1 through July 1) saw 2,836 juveniles offered at auction, with 2,191 selling for a combined $206,754,833.

Three-year-old (“sophomore”)

Three-year-old Thoroughbreds, also known as “sophomores,” receive more attention than any other age group. Only three-year-olds are eligible to compete in the coveted Triple Crown races: the Kentucky Derby (G1), Preakness S. (G1), and Belmont S. (G1).

During the winter, spring, and summer, three-year-olds are still developing and can quickly progress or regress compared to their juvenile racing form. But by fall, their major growth spurts are over, and three-year-olds are more mature and capable of competing on even terms against older horses.

Once a horse turns three years old, their racing potential is relatively clear, so there isn’t a wide need to sell or buy them at auction. Instead, three-year-olds can change hands by private sale or by competing in claiming races, where each participant can be “claimed” (purchased) for a predetermined amount.

Older horse/mare

Horses aged four and older are broadly referred to as “older” horses (or older mares, if female), without addressing their exact age. While races restricted exclusively to four-year-olds do exist, you’re more likely to see races open to “three year olds and upward” or “four years old and upward,” allowing horses of many ages to compete against each other.

Older horses are considered fully mature, with their peak performances typically coming at the ages of four and five. The best racehorses are typically retired for breeding purposes before they reach the age of six, though exceptions aren’t uncommon and lower-level horses sometimes race to the age of 10 or beyond.

Congratulations! The next time you read how Horse A “sold for $1 million as a yearling” and “appears bred to thrive as a juvenile,” you’ll know exactly what the lingo means.