An illustration of the earliest-known horse, Sifrhippus, dwarfed next to a modern domestic horse. Courtesy of Danielle Byerley, Florida Museum of Natural History
Posted on 03/02/2012 9:03:13 AM PST by null and void
An illustration of the earliest-known horse, Sifrhippus, dwarfed next to a modern domestic horse. Courtesy of Danielle Byerley, Florida Museum of Natural History
As scientists continue developing climate change projection models, paleontologists studying an extreme short-term global warming event have discovered direct evidence about how mammals respond to rising temperatures. In a study appearing in Science February 24, 2012, researchers from eight institutions, led by scientists from the University of Florida and University of Nebraska, found a correlation between temperature and body size in mammals by following the evolution of the earliest horses about 56 million years ago: As temperatures increased, their body size decreased.
“Horses started out small, about the size of a small dog like a miniature schnauzer,” said co-author Jonathan Bloch, associate curator of vertebrate paleontology at the Florida Museum of Natural History on the UF campus. “What’s surprising is that, after they first appeared, they then became even smaller and then dramatically increased in size, and that exactly corresponds to the global warming event, followed by cooling. It had been known that mammals were small during that time and that it was warm, but we hadn’t understood that temperature specifically was driving the evolution of body size.”
Sifrhippus, the earliest-known horse, first appeared in the North American fossil record during the Paleocene-Eocene Thermal Maximum. During this 175,000-year climate event, increased concentrations of carbon dioxide in the atmosphere and oceans caused average global temperatures to rise 10 to 20 degrees. By analyzing the size and isotopes of fossils collected in Wyoming’s Bighorn Basin, researchers traced the evolution of Sifrhippus from an estimated 12-pound animal that shrank during a 130,000-year period by about 30 percent to 8.5 pounds — the size of a small house cat — then increased to about 15 pounds during the next 45,000 years.
“This is the highest-resolution terrestrial record of its kind from anywhere in the world, and it shows how climate changed in Wyoming at that time,” said lead author Ross Secord, who began geochemical analysis of the horse teeth and other mammals as a postdoctoral researcher with Bloch before joining the University of Nebraska-Lincoln in 2008. “When Jon and I started plotting oxygen data from the mass spectrometer, we could immediately see that the shifts in size of horses and temperature were mirror images of each other.”
Bloch said the project began about seven years ago when former UF student and study co-author Stephen Chester, now an anthropology doctoral candidate at Yale University, measured horse teeth that seemed to be too large for their age and became smaller through the geologic section. The findings raise important questions about how animals might respond to future rapid climate change.
“We’re seeing about a third of the mammals getting smaller, and some of them getting a lot smaller, by as much as half of their original body size,” Secord said. “Because warming happened much slower during the Paleocene-Eocene Thermal Maximum, mammals had more time to adjust their body size. So, it’s not clear that we’re going to see the same thing happening in the near future, but we might.”
Philip Gingerich, who first recorded the phenomenon of decreasing body size during the Paleocene-Eocene Thermal Maximum in 1989, said the study documentation clearly demonstrates the relationship between temperature and body size. He agrees this may occur as a result of current warming patterns.
“I joke about this all the time — we’re going to be walking around three feet tall if we keep going the way we’re going,” said Gingerich, a researcher at the University of Michigan and director of its Museum of Paleontology. “Maybe that’s not all bad and, if that’s the worst it gets, it will be fine. You can either adapt, or you go extinct, or you can move, and there’s not a lot of place to move anymore, so I think it’s a matter of adaptation and becoming smaller.”
Researchers also analyzed correlations with aridity and carbon dioxide levels, but found temperature to be the most likely driving factor in body size. Although little is known about how animals arrived in North America at that time, the Paleocene-Eocene Thermal Maximum (PETM) is a significant event in geologic time in terms of mammalian history, Bloch said.
“The PETM is really important, because it marks the beginning for the first appearance of several major groups of mammals, including crown-group primates (ancestors of modern primates) and the first even- and odd-toed modern ungulates (mammals with hooves),” Bloch said. “This sets the scene for the entire diversity of animals we see on the planet today.”
Study co-authors include Doug Boyer of Brooklyn College, Aaron Wood of South Dakota School of Mines and Technology and the Florida Museum, Scott Wing of the Smithsonian Institution National Museum of Natural History, Mary Kraus of the University of Colorado, Francesca McInerney of Northwestern University and John Krigbaum of UF.
How do they know which is the cause and which is the effect?
Carbon Dioxide’s fault?
How does that correlate to temperature again? Oh yea. The consensus thing.
The whole study (if that’s what they call it) was based on a premise that is theorized at best and fictional at worst.
Guess who will now peer review this and announce that humans will start to shrink in the years to come, nevermind the history of human evolution over the past 100 years.
The article has a very misleading title. The horse shrunk from Big-House-Cat size to Average-House-Cat size, a weight reduction of 30%.
As written, it gives one the impression that you go from a Belgian to an Eohippus or house cat size due to global warming (I’m sure the editor had no such bias).
Animal Kingdom Weirdness?
“I joke about this all the time — we’re going to be walking around three feet tall if we keep going the way we’re going,” said Gingerich, a researcher at the University of Michigan and director of its Museum of Paleontology. “Maybe that’s not all bad and, if that’s the worst it gets, it will be fine. You can either adapt, or you go extinct, or you can move, and there’s not a lot of place to move anymore, so I think it’s a matter of adaptation and becoming smaller.”
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It is really getting difficult to keep a polite dispositon when dealing with people who are this idiotic. This man actually thinks that human progress, capitalism, and propserity will drive us to being three feet tall. He does not deserve even any respect at all but deserves contempt. He is driven by upholding political lies and that is all. He deserves ridicule and no respect. He is dangerous given that he holds a position that should be respected and then pushes such lies.
Obviously, this is Bush’s fault.
Yes, if I recall correctly, the so called horse they are talking about is not related to the horse of today. That little thing died out, so you can make up any silly story why. But the main reason was it was slower that the animal that ate it.
ping
If this is true, my great grandkids will be the size of North Koreans.
Why, in just 42 years of evil man capitalism-caused global warming and CO2 emissions, the size of the horse has gone from this:
to this:
So Clydesdale horses used to be bigger?
And North Koreans will be the size of pygmies.
And pygmies will be the size of..... uh....something.
Mice?
:0)
If the story was true, it isn’t so.
I’m confused. They say horses get smaller due to rising temperatures, then say that horses started off small and got bigger.
I thought cold water caused shrinkage.
Even if these alarmists were correct in their conclusions, so what!
Smaller mammals means less consumption. Adaptation is natural and evolutionary. Isn’t this what they wanted from us?
Yes, this might be a good candidate...
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