Skip to Content

Gender in Horse Racing: Male vs Female Racehorses

Last updated: January 5, 2024

By: Miles HenryFact Checked

In the world of horse racing, where every second and stride counts, have you ever paused to consider the role of gender on the racetrack? While it’s common to see races divided by gender, the question of whether male or female horses dominate the sport remains a topic of subtle yet significant interest.

Horse racing often showcases the prowess of thoroughbreds in a gender-specific context. However, the underlying dynamics of how male and female racehorses perform, train, and contribute to the sport are aspects that often go unnoticed. In a world where the spotlight typically falls on speed and endurance, the influence of gender on these equine athletes presents an intriguing angle often overlooked by casual observers.

This article seeks to explore the nuanced roles of male and female racehorses in the competitive landscape of horse racing. We will navigate through the historical achievements, training differences, and the impact of gender in shaping the careers of these racehorses. Whether you’re a horse racing fan or simply curious about the sport, this exploration aims to provide a clearer understanding of how gender plays a role in the world of horse racing.


In 1915, Regret, became the first filly to win the Kentucky Derby.

Historical Context: Evolution of Gender Roles in Racing

The history of horse racing is rich and varied, with gender roles evolving significantly over time. Traditionally, the sport was dominated by male horses, often perceived as more powerful and faster. This belief stemmed from early racing practices where strength and speed were the sole focus, and male horses, particularly stallions, were favored for their muscular build and aggressive racing style.

However, as the sport evolved, so did the understanding of what makes a successful racehorse. It became clear that factors like agility, endurance, and intelligence were just as crucial, qualities not limited by gender. This realization opened the track to more female horses, challenging the long-held notion of male dominance in the sport.

Notable Milestones

Female racehorses have had a remarkable impact on the sport, breaking barriers and setting records that stand as a testament to their capabilities. One of the earliest and most notable milestones was achieved by Regret, a filly who made history in 1915 by winning the Kentucky Derby.

This victory was not just a win in a race; it was a groundbreaking moment that challenged the prevailing perceptions of female racehorses. Another significant achievement was by Winning Colors, one of only three fillies to win the Kentucky Derby in its storied history.

Her victory in 1988 was a powerful statement about the capabilities of female racehorses in competing at the highest levels. More recently, the legendary mare Zenyatta captivated the hearts of racing fans worldwide with her impressive 19-race winning streak, a feat that further solidified the place of female racehorses in the sport.

Her remarkable career, culminating in a breathtaking performance in the 2009 Breeders’ Cup Classic, showcased not just her exceptional talent but also the evolving role of mares in horse racing.

These milestones are not just historical footnotes; they represent a broader shift in the sport, where gender is becoming less of a defining factor in racing success. The achievements of these remarkable female racehorses have paved the way for more inclusive and diverse competition, enriching the sport in the process.

Picture of a horse race of fillies and mares.
A horse racing of fillies and mares.

Debunking Myths

The world of horse racing is riddled with myths and misconceptions, particularly regarding the capabilities and roles of male and female racehorses. Let’s address and debunk some of the most common myths:

  1. Myth: Male horses are always faster than females.
    • Reality: Speed in racehorses is influenced by a multitude of factors, including breeding, training, and individual physiology, not just gender. While male horses are often perceived as faster, many female racehorses have proven to be equally, if not more, capable in terms of speed. For instance, the legendary mare Zenyatta’s 19-race winning streak is a testament to this.
  2. Myth: Female racehorses are not as resilient as males.
  3. Myth: Stallions are more competitive and aggressive, making them better racehorses.
    • Reality: While stallions may exhibit more natural aggression due to testosterone, competitiveness in racing is not solely a trait of male horses. Mares and fillies often exhibit strong competitive spirits. The key to a racehorse’s success lies in its training, temperament, and innate abilities, rather than just aggressive behavior.


Research from equine sports scientists and historical race records provide evidence that contradicts these myths. For example, studies have shown that the physiological and biomechanical attributes contributing to a racehorse’s performance are not exclusively found in one gender.

Additionally, historical race data from events like the Triple Crown races reveal that female racehorses have not only competed at the highest levels but have also emerged victorious against their male counterparts.

In a relevant study published in the FASEB Journal, researchers found that while human athletes show a notable sex-based difference in elite performance, such differences are not apparent in thoroughbred horses and greyhound dogs. This research underscores that the physiological traits influencing athletic performance in racehorses transcend gender boundaries (FASEB J. 2021 May; 35(5): e21562).

The myths surrounding the inherent superiority of one racehorse gender over the other in terms of performance do not hold up under scrutiny. The achievements of female racehorses stand as a clear counterpoint to these misconceptions, highlighting the importance of evaluating each horse as an individual athlete.

Picture of my female yearling.
My female yearling “Aunt Addie.”

Anatomy and Physiology

While there are physiological differences between male and female racehorses, the impact on racing performance is nuanced and influenced by a range of factors. Training and care practices are adapted to meet the individual needs of each horse, with considerations for their physical and behavioral traits.

Physical Differences

The physiological differences between male and female racehorses, while subtle, can influence their racing performance. Understanding these distinctions is key to appreciating how each gender contributes uniquely to the sport.

  1. Size and Muscle Mass: Generally, male horses, especially stallions, tend to be larger with more muscle mass compared to females. This can translate into a longer stride and potentially more power, which is advantageous in certain racing conditions. However, this is not a definitive rule, as the efficiency of a horse’s stride and its endurance are also critical factors in racing.
  2. Center of Gravity: Mares often have a lower center of gravity, which can be beneficial for agility and maneuverability on the track. This can be particularly advantageous in races with tight turns or where tactical racing is required.
  3. Endurance: Some studies suggest that female racehorses may have better endurance capabilities, although this is a subject of ongoing research. The ability to maintain speed over longer distances is a complex trait influenced by both physiological and environmental factors.

A recent study published in the Journal of Veterinary Medical Science investigated sex differences in the development of cervical spinal cord and spinal canal in Thoroughbred horses. The research found that male horses had significantly larger cervical spinal cord volumes and a higher cervical spinal cord-to-spinal canal volume ratio compared to female horses.

These findings suggest that younger male horses have a narrower interspace between the cervical spinal cord and spinal canal, potentially influencing the development of cervical vertebral stenotic myelopathy (CVSM), a common neurological disease in young adult Thoroughbreds.

This study highlights the importance of considering sex differences in the anatomical development of racehorses, which could have implications for their training and healthcare” (J Vet Med Sci. 2022 Oct; 84(10): 1363–1367).

Training and Care

When it comes to training and care, the approach can vary slightly based on the gender of the racehorse, although the core principles remain the same.

  1. Training Regimen: Training programs are generally tailored to the individual horse rather than strictly by gender. However, trainers might adjust training intensity or methods based on the temperament and physicality of the horse, which can sometimes correlate with gender. For instance, a more spirited stallion might require a different approach compared to a mare.
  2. Nutritional Needs: Nutritional requirements are largely similar, but there can be adjustments based on the size and muscle mass of the horse. Stallions might require a diet higher in calories to support greater muscle mass, whereas mares might need a diet adjusted for optimal reproductive health and endurance.
  3. Health and Reproductive Care: Mares require specific reproductive care, especially if they are part of a breeding program alongside their racing career. This includes monitoring their estrous cycles and ensuring their health during the breeding season. Stallions, particularly those used for breeding, also require specific care to maintain their health and fertility.
  4. Behavioral Management: Behavioral differences can necessitate varied approaches in handling and training. Stallions might exhibit more dominant or aggressive behaviors, requiring experienced handling to ensure safety and focus during training. Mares might require sensitive handling during certain periods of their estrous cycle.

A comprehensive study on Standardbred trotter horses, investigated the relationship between fitness parameters measured during treadmill tests and racing outcomes. The study found that maximum speed and speed at the aerobic threshold were significantly correlated with racing results, both before and after examination, as well as lifetime career outcomes.

This research highlights the importance of specific fitness parameters as predictors of racing performance and career potential in racehorses, offering valuable insights for training and performance evaluation in the sport” (PLOS ONE, 2023).

Picture of the great racehorse Man o' War.
Man o’ War

Famous Racehorses: Case Studies

The legendary status of the following horses, irrespective of their gender, demonstrates that excellence in racing is not confined to one gender but is a testament to the extraordinary capabilities of thoroughbreds as a breed.

Male Champions

  1. Secretariat (1970-1989): Often hailed as one of the greatest racehorses in history, Secretariat captured the public’s imagination with his extraordinary performance in the 1973 Triple Crown. He set records in all three events, including a staggering 31-length victory in the Belmont Stakes, a record that stands to this day.
  2. Man o’ War (1917-1947): Another legend of the racetrack, Man o’ War won 20 of his 21 races. His dominance in the early 20th century set a high bar for thoroughbred racing, and his only loss, famously known as “The Upset,” became a part of racing folklore.
Zenyatta 2009 Breeders Cup Classic (4087747688)

Zenyatta at the 2009 Breeders Cup By Lisa Andres, USA, CC BY 2.0

Female Champions

  1. Ruffian (1972-1975): Known for her speed and spirit, Ruffian was an undefeated filly until her tragic final race. She won 10 consecutive races, often by wide margins, and set new stakes records in eight of them, showcasing the prowess of female racehorses.
  2. Zenyatta (2004-): With a career marked by 19 wins out of 20 starts, Zenyatta became a fan favorite for her dramatic come-from-behind victories. Her win in the 2009 Breeders’ Cup Classic against a field of males highlighted her exceptional racing ability and charisma.

Comparative Analysis

The achievements of these champions, both male and female, underscore the gender parity in horse racing. Secretariat’s and Man o’ War’s records are well-celebrated in the annals of horse racing history, showcasing the strength and speed often attributed to male racehorses. On the other hand, Ruffian’s and Zenyatta’s careers highlight the endurance, agility, and competitive spirit of female racehorses.

Here is a YouTube video showing Winx’s dominance in horseracing

Video about the great racehorse Winx.

Current Trends and Statistics

The current trends and statistics in horse racing indicate a move towards greater gender parity, both in terms of participation and recognition. This evolution reflects a broader understanding of the capabilities of racehorses, transcending traditional gender norms.

Recent Data

The landscape of horse racing continues to evolve, with gender distribution being an area of notable change. Recent statistics shed light on the current state of gender representation in the sport:

  1. Participation Rates: As of the latest data, the split between male and female racehorses participating in major races is approximately 60-40, with males still maintaining a majority. However, this gap has been narrowing compared to past decades.
  2. Winning Statistics: Analysis of race outcomes shows that while male horses often win a higher percentage of races, the margin is not as wide as it once was. Female racehorses have been steadily closing this gap, particularly in high-stakes and high-profile races.
  3. Breeding Trends: There’s an increasing interest in breeding female racehorses with strong track records, reflecting a growing recognition of their value not just as competitors but also as key contributors to the sport’s future.

Changing Trends

The horse racing industry is witnessing several shifts regarding gender:

  1. Increased Recognition of Female Racehorses: There’s a growing appreciation for the achievements of female racehorses, with more attention being paid to their performances in major races. This shift is partly driven by notable successes of mares and fillies in traditionally male-dominated events.
  2. Gender-Specific Races: While gender-specific races still exist, there’s an increasing number of mixed-gender races, providing more opportunities for direct competition between male and female racehorses.
  3. Training and Management: The approach to training and managing racehorses is becoming more tailored and individualized, with less emphasis on gender-based strategies. This change reflects a deeper understanding of the unique needs and capabilities of each horse.
  4. Public Interest and Perception: The perception of female racehorses among the public and within the racing community is shifting. There’s a growing recognition of their capabilities and a more balanced view of gender roles in the sport.
Picture of my two year old filly in training.  Gender in horse racing doesn't affect her training.
My filly is on a walking wheel after training.

Evolving Perspectives in Horse Racing

While the allure of lucrative stud fees has historically tilted preferences toward male racehorses, the industry is witnessing a transformative shift. Stallions like Tapit, commanding staggering stud fees, have long been the financial pillars in the racing world. However, the landscape is evolving as the racing community begins to recognize the untapped potential of female racehorses.

The Rising Value of Female Racehorses

The journey of female racehorses, traditionally constrained by their eleven-month gestation period, is being reevaluated. This biological factor, once seen as a limitation, is now part of a broader narrative that includes their significant achievements on the track. The industry is gradually acknowledging that the value of a racehorse extends beyond breeding potential to include their racing prowess and the legacy they can create.

Overcoming Outdated Beliefs

Historical data, such as the dominance of male horses in races like the Kentucky Derby, has often been misinterpreted to undervalue female racehorses. However, emerging performance data and recent successes are challenging these outdated beliefs. The industry is beginning to appreciate that factors like strategic race targeting and qualifying procedures play a significant role in these historical trends.

Celebrating Female Achievements

A notable indicator of this change was the spotlight on a filly as the top-selling yearling at the Keeneland auction in 2019. Such milestones are not just financial triumphs but also symbolic victories against long-standing misconceptions. They herald a future where the talents and capabilities of female racehorses are celebrated and respected on par with their male counterparts.

One exemplary figure in this narrative is Winx, a dark bay mare from Australia. Her extraordinary racing record includes 33 consecutive victories, featuring a world record of 25 Grade I wins. With a total of 43 races, Winx achieved 37 first-place finishes and 3 seconds, matching the record of the legendary Phar Lap and earning the title of the world’s all-time money winner.

Her undefeated streak from May 2015 to April 2019 cements her status as one of the greatest racehorses, male or female. Winx’s achievements, alongside those of other notable female racehorses like Zenyatta and Ruffian, underscore the emerging respect and rising value of female racehorses in the industry.

Personal Reflection

Reflecting on these industry changes, my recent focus on purchasing female horses is a testament to their rising value and potential. It’s a strategic decision that aligns with the shifting dynamics of the racing world, where the prowess and achievements of female racehorses are increasingly being recognized and rewarded.

Picture of an open turf race with both genders competing.
Open turf race that includes both genders.

Conclusion: Gender in Horse Racing

In exploring the fascinating world of horse racing, we’ve delved into various aspects that highlight the roles and perceptions of gender in the sport. From debunking common myths to examining the physical differences and achievements of male and female racehorses, it’s clear that the sport is much more nuanced than traditional views suggest.

Historical milestones have shown that female racehorses are not just participants but champions in their own right, capable of rivaling and even surpassing their male counterparts. Current trends indicate a shift towards greater gender parity, with an increasing appreciation for the individual merits of each horse, irrespective of gender.

Looking ahead, the future of horse racing seems to be steering towards a more inclusive and diverse landscape, where gender plays a less defining role, and the focus is on the unique qualities of each equine athlete.

As we witness these changes unfold, one can’t help but wonder: Are we on the cusp of a new era in horse racing, where the line between stallion and mare blurs, giving way to a sport that celebrates excellence without gender bias?

Feedback Request

We value your thoughts and experiences! If this exploration into the world of horse racing and the role of gender has sparked any insights, stories, or opinions, we’d love to hear from you. Please feel free to leave a comment below sharing your perspectives.

Have you witnessed a race that defied gender stereotypes? Do you have a favorite male or female racehorse? Your experiences enrich the conversation and deepen our understanding of this fascinating sport.

Social Sharing

If you found this article enlightening and thought-provoking, help spread the word! Share it on your social media platforms to ignite a discussion among your friends and followers. Whether you’re a seasoned racegoer or new to the world of horse racing, your share can contribute to broadening the conversation about gender roles in this thrilling sport.

Connect with Me

  • Email: [email protected]
  • Social Media: Follow me on Facebook for daily updates, tips, and insights into the world of horses.
  • Website: Visit my website, for more articles, resources, and information about my work.

Poll Question


Has a female horse ever won the Kentucky Derby?

Yes, three female horses won the Kentucky Derby. The most recent was Winning Colors in 1988. Genuine Risk won it in 1980, and Regret was the first female Kentucky Derby winner; she performed her feat in 1915. Check out this article: What Horses Won the Triple Crown? Meet 13 Great Champions

Are male horses faster than female horses?

Generally speaking, male horses are faster, taller, and stronger than their female counterparts. They also outnumber female horses on the racetrack and hold almost every relevant speed record. However, some outliers can run faster than the males, like the ones mentioned in this article.