According to conventional notions, horses simply became bigger over time and switched from being diminutive shrub nibblers to the statuesque, grass-eating masters of the open plains, said Bruce MacFadden, a UF paleontologist whose article appears in this week's issue of the journal Science. But the new horse sense is that the equine mammals are adaptable critters whose size, diet and range depended on geography and climate, he said.
"The old ideas about how horses evolved made for a fairly simple and tidy story," said MacFadden, whose 1992 book "Fossil Horses" is considered the definitive work on the subject. "But many of the concepts about horse evolution that came into being during the 20th century are now outmoded, giving way to an understanding of the fossil horse sequence that is much more complex."
Because horses have been around a long time, learning about their evolution provides unusual insight into the patterns of evolution in general, said MacFadden, who works at UF's Florida Museum of Natural History. "Horses are a very good example because there is a long, continuous fossil sequence of horses extending 55 million years in North America, providing the tangible evidence to trace individual steps or changes in evolution over a prolonged period of time," he said.
MacFadden said horses are credited with shaping human history more than any other domesticated animal. However, it behooves us to be cautious when accepting other beliefs about the popular animals, he said.
Children often learn in social studies classes how the Spaniards brought horses to the New World in the 1500s, eventually producing vast herds of wild horses on the prairies and helping to create America's legendary cowboys, MacFadden said. But the f
Contact: Bruce MacFadden
University of Florida