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
A look at how acidifying oceans could threaten the Dungeness crab, one of the most valuable fisheries on the U.S. West Coast. Watch the video.
is now available for mobile devices at e360.yale.edu/mobile
An aerial view of why Europe’s per capita carbon emissions are less than 50 percent of those in the U.S. View the photos.
An indigenous tribe’s deadly fight to save its ancestral land in the Amazon rainforest from logging. Learn more.
video series looks at the staggering amount of food wasted in the U.S. – a problem with major human and environmental costs. Watch the video.
Residents of the Chocó Rainforest in Ecuador are choosing to plant cacao over logging in an effort to slow deforestation.
Watch the video.
Tribal people and ranchers join together to stop a project that would haul coal across their Montana land. Watch the video.