24 Feb 2012:
Warming Climate Caused
Early Horse Species to Shrink, Study Says
A new study suggests that the earliest known horse species shrank significantly in size over a 135,000-year span
as a consequence of a warming climate. Using geochemical testing and measurements of fossilized teeth dating back more than 50 million years, U.S. researchers found that a 30-percent decrease in the body size of the species, Sifrihippus sandae
, corresponded closely with changes in global temperatures. As the average global temperature rose by about 10 degrees F during the first 135,000 years of that period — known as the Paleocene-Eocene Thermal Maximum (PETM) — the early horse, which lived in the forests of North America, declined in size from about 12 pounds to about 8.5 pounds, presumably because a declining amount of available oxygen. According to the study, published in the journal Science
, the species regained much of its size during the final 45,000 years of the PETM, bulking up to about 15 pounds. Researchers say the so-called “dwarfing” phenomenon could provide insights into how animals will respond to a projected increase in global temperatures in the coming centuries. “One of the questions is, ‘Are we going to see the same kind of response?’” said Ross Secord, a researcher at the University of Nebraska-Lincoln.
Yale Environment 360 is
a publication of the
Yale School of Forestry
& Environmental Studies
Yale Environment 360
articles are now available in Spanish and Portuguese on Universia
, the online educational network. Visit the site.
Business & Innovation
Policy & Politics
Pollution & Health
Science & Technology
Antarctica and the Arctic
Central & South America
Photographer Robert Wintner documents the exquisite beauty and biodiversity of Cuba’s coral reefs, which are largely intact thanks to stifled coastal development in the communist nation. View the gallery.
is now available for mobile devices at e360.yale.edu/mobile
The Warriors of Qiugang
, a Yale Environment 360
video, chronicles a Chinese village’s fight against a polluting chemical plant. It was nominated for a 2011 Academy Award for Best Documentary Short.
Watch the video.
Top Image: aerial view of Iceland
. © Google & TerraMetrics.
A three-part series Tainted Harvest
looks at the soil pollution crisis in China, the threat it poses to the food supply, and the complexity of any cleanup. Read the series.