Evolution: Characteristics Dependent on Geography, Climate

Research suggests that horses’ size, diet, and distance traveled depended on external factors.
Share
Favorite
Close

No account yet? Register

ADVERTISEMENT

While conventional wisdom suggests that horses simply became bigger throughout history and changed from diminutive shrub nibblers to the masterful grass-eating specimens we have today, current evidence seems to discount that theory. Bruce MacFadden, MPh, PhD, an equine forensic paleontologist at the University of Florida, has been working with horse evolution since the 1970s, and he is considered a world authority on equine evolution. He penned an article for the March issue of Science that suggested time wasn’t the only factor in the evolution of equids. His fossil horse study suggested horses were adaptable creatures whose size, diet, and distance traveled also depended on such factors as geography and climate.

"Modern-day horses, zebras, asses, and their kin are just a small part (of the equid family)," said MacFadden. "They are the tip of the iceberg in terms of us understanding what horses have been like (throughout history). The family tree of horses is much more complicated than is portrayed in textbooks and museum exhibits today."

MacFadden’s research on this topic has been going on for more than 12 years, and it focuses on the chemical makeup of fossilized equine teeth. By analyzing the carbon content of teeth, MacFadden can determine a horse’s diet and migration, because some foods were readily available and some weren’t. The size of the horse can also be determined, since body size and tooth size are proportional.

MacFadden says scientists once thought the more primitive horses, which lived 55-20 million years ago, were primarily browsers that gave way to grazing animals in the late Miocene period. But this linear evolution might not be as straight as once thought. MacFadden said there are quite a few "branches" to the equine family tree, because some horses became mixed feeders (eating both leaves and grasses) during this period. Also at this time, some horses grew larger while others became smaller or remained the same size

Create a free account with TheHorse.com to view this content.

TheHorse.com is home to thousands of free articles about horse health care. In order to access some of our exclusive free content, you must be signed into TheHorse.com.

Start your free account today!

Already have an account?
and continue reading.

Share

Written by:

John V. Wood is an Emmy Award-winning journalist, and now teaches his craft to high school students in North Carolina. Wood has been published in numerous national magazines/newspapersover his career, and published his first book in June 2010. Wood currently lives in Willow Spring, NC.

Related Articles

Stay on top of the most recent Horse Health news with

FREE weekly newsletters from TheHorse.com

Sponsored Content

Weekly Poll

sponsored by:

Where do you primarily feed your horse?
276 votes · 276 answers

Readers’ Most Popular

Sign In

Don’t have an account? Register for a FREE account here.

Need to update your account?

You need to be logged in to fill out this form

Create a free account with TheHorse.com!