Men Are
Faster Than Women. But Does That Mean Bets Should Always Be Placed On
Colts?
New research
sheds light on gender differences, running and racing animals
San Diego, CA
–Was Lassie only the second fastest collie in the valley? Was Roy Rogers’s
horse Trigger faster than Dale Evans’s filly, Buttermilk? Men
are readily acknowledged as faster runners than women. Can the same
assumption be made about gender in horses and dogs?
Background
It’s not too hard to see why that assumption might be made. Sir
Roger Bannister ran the first sub-four minute mile in 1954. Forty-eight
years later, the men’s record for the mile is
3:43.13; a Russian woman holds the corresponding record for women at
4:12.56. Those who organize competitive track and field events realize that
although a given individual woman may be faster than a given
individual man, this gender difference is apparent at levels from amateur to
elite.
Competitive
racing standards are more egalitarian in the animal kingdom. Thoroughbred
(flat racing) and Standardbred (harness racing) horse races are generally
divided by gender. However, female horses (fillies) have been outright
winners of some premier events such as the Kentucky Derby, Breeder’s Cup
races, and the Hambletonian trotting race. Considering that fillies do
enter the winner’s circle, a researcher wondered if a consistent gender
difference in running performance does exist in horses, and if so how the
magnitude of that difference compares to that seen in humans. The
investigation also extended to an examination of a gender difference in
running speed of the dog, another competition species. Unlike human and
horse races, Greyhound races are not segregated by gender, suggesting that
these dog owners do not perceive a gender difference in running ability.
In male and
female running ability, it is appropriate to ask if there are physiological
parameters known to affect athletic ability. In humans and animals, maximal
aerobic capacity, the maximum rate at which the body can use oxygen to
produce energy, is often used as an index of endurance running ability.
This index is significantly greater in men than women, even when body mass
is taken into account. The higher maximum aerobic capacity of men vs. women
has been verified repeatedly, in young and old, athletic and sedentary. The
differences between the sexes that underlie men’s athletic advantage include
body composition (percent body fat versus lean body mass), cardiac size,
blood volume, and hemoglobin concentration. For a given total body weight,
men have more lean body mass and less fat. Men also have larger hearts and
a greater maximum cardiac output (liters of blood/minute) then women.
A sexual
dimorphism does occur in both horses and dogs in terms of overall size –
males are generally taller and heavier than females. Body composition is
seldom measured in these species, although subjectively most horsemen feel
that stallions are more muscular than mares. Gender-based comparisons of
heart size, blood volume, and hemoglobin concentration have not been
published for these species. Furthermore, the factors that limit maximum
aerobic capacity in the horse appear to be associated with the lung, rather
than with the cardiovascular system as in humans. Thus, evidence to support
a gender difference in maximum aerobic capacity in horses and dogs is
lacking, primarily because the possibility of a gender difference in oxygen
consumption of horses or dogs has never been systematically investigated.
Nevertheless, female horses are rarely run against males.
The Study
The author of “Gender Difference In Running Speed: Humans Versus
Horses And Dogs,” is Pauline Entin, PhD, Assistant Professor, Department of
Exercise Science, Northern Arizona University, Flagstaff, AZ. Dr. Entin
will present her findings at the upcoming scientific meeting, “The Power of
Comparative Physiology: Evolution, Integration and Application.” The
meeting, being sponsored by the American Physiological Society (APS), is
being held August 24-28, 2002, at the Town & Country Hotel, San Diego, CA.
This study sought
an empirical answer to the question of a gender difference in running
performance in horses and dogs by comparing actual racing velocities. Given
the observation that horse races, both flat racing and harness racing, are
segregated by gender whereas Greyhound races are not, the research
hypothesized that a difference between the sexes would occur in horses but
not dogs.
Methodology
Data on horse and dog running speeds were obtained from several
different on-line sources.
-
Thoroughbred
Horse (flat racing): Data were obtained from the Daily Racing Form
on-line from May through August, 2001. Tracks in three states were used:
Belmont and Saratoga racetracks in New York, Santa Anita and Hollywood
tracks in California, and Churchill Downs and Keeneland racetracks in
Kentucky. The distance of the race was converted to meters and the
winner’s average velocity (m/s) was computed by dividing the distance by
the winning time. The races were split into two categories prior to
analysis: less than or equal to one mile (< 1609 m) and greater
than one mile (> 1609 m). A total of 330 races were used for this
analysis.
-
Standardbred
Horse (harness racing): Track records for eight different North
American racetracks were used. Track records are kept separately for
trotters and pacers. All records are for one mile, the standard distance
for harness racing. Variables recorded included: track, record time for
one mile (1609 m), record holder’s category (trotter or pacer), record
holder’s age, record holder’s gender. Average velocity was calculated as
1609 m divided by the record time. Analyses were done separately for
trotters and pacers as pacing is known to be slightly faster and there is
no cross-over between trotters and pacers. A total of 191 records were
used; 95 for trotters and 96 for pacers.
-
Greyhound
Dog: Data was obtained from records kept on-line by Bluffs Run
racetrack, Iowa, for races run between May 2001 and March 2002. All races
were run over either 5/16th mi (503 m) or 3/8th mi
(603.5 m). To account for the affect of distance, analyses were done
separately for the two race lengths. The effects of month of year, race
class, winner’s weight, winner’s age, and winner’s gender on velocity were
tested via multiple regression (SPSS). A total of 169 races were used.
Results
Regression analysis of actual race data revealed a small but
significant effect of gender on the racing velocities of Thoroughbred horses
and Standardbred pacers, but not Standardbred trotters or dogs. It is
notable that in all cases males held a slight advantage over females,
although this difference was not significant for the trotters and dogs.
When compared to the approximately 10 percent gender gap in peak running
speeds of humans, the difference in the animals was small – no greater than
1.2 percent.
The relatively
small difference between the genders in both horses and dogs agrees with the
lack of evidence of relevant physiological dimorphism in both species.
Although the difference in the horses was significant, the one percent
gender gap could be explained by training methods or psychological factors
as well as physiological attributes. It is a widely held belief among
racehorse trainers that female horses should not be trained as hard as male
horses, and trainers are loathe to enter female horses in races that are
also open to males. Greyhound races are not segregated, presumably
signifying that Greyhound owners and trainers believe that females can
compete successfully with males.
Conclusions
Given the evolution of the horse as a prey species and the ancestors
of the dog as a predatory species, both dependent on running, it is tempting
to speculate that natural selection operated on the running ability of both
males and females of these species. In contrast, archeological evidence
suggests that human ancestors were tool users and may have had
gender-specific tasks at least as much as one million years ago, possibly
lessening the importance of running speed particularly in females. This
analysis is strictly speculative, yet it is clear that humans have
selectively bred both racehorses and Greyhounds for speed in both genders
for several hundred years, whereas humans do not select their own mates
based solely on running ability.
In conclusion, although male horses and dogs do hold a slight speed
advantage over conspecific females, the difference is an order of magnitude
smaller than that seen in humans (one percent versus 10 percent). Factors
other than physiological differences may explain why horse races are
traditionally segregated by gender.
- end -
The American Physiological Society (APS) is one of the
world’s most prestigious organizations for physiological scientists. These
researchers specialize in understanding the processes and functions by which
animals live, and ultimately underlie human health and disease. Founded in
1887 the Bethesda, MD-based Society has more than 10,000 members
and publishes 3,800 articles in its 14 peer-reviewed journals each year.
***
EDITOR’S NOTE: For further information or to
schedule an interview,
contact Donna Krupa at 703.967.2751 (cell), or by email at
djkrupa1@aol.com.
