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The White House is responding to an I-Team investigation into wild horses. They are protected under federal law as "living symbols" of the nation's pioneer spirit. But now, advocates are worried what the Donald Trump presidency could mean for the future of the mustangs. Dan Noyes has a long history reporting on this issue, and he's back with the latest.

It's been a problem for decades. Some ranchers have been able to ignore the law and the government's policy, purchasing wild horses and sending them to slaughter for food.

Month by month, year after year, this is how the federal government tries to maintain a healthy wild horse population -- using helicopters to scare herds to stampede, so they can capture what they believe are excess mustangs.

BLM Spokesman Jeff Fontana tells the I-Team, "It's all about establishing populations that the range land can support."

But the round-ups often kill or injure horses.

During the Owyhee round-up in Nevada two months ago, the Bureau of Land Management or BLM reports on its website 18 horses died. But public records show many more died -- a total of 48 -- in the round-up or in government corrals after: broken necks or backs, leg or pelvis fractures, some causes of death listed as "unknown", others as "pre-existing conditions".

"I've seen foals that have died because they have literally run their feet off," says Ellie Phipps Price.

She's the American Wild Horse Campaign President, and owns a Sonoma County sanctuary with 240 wild horses.

She tells Dan Noyes, the BLM allows many more cattle and sheep owned by private ranchers to graze on public land, compared to wild horses.

"The herd sizes are so small in some places, they're not genetically viable," says Phipps Price. "So we are at risk of losing these amazing, iconic animals."

Phipps-Price cites a National Academy of Sciences study from 2013 that criticized the government, saying:

-- its wild horse population numbers are "unsubstantiated estimates,"

-- that there's "a lack of evidence that management decisions are informed by science."

-- It urged the BLM to use "contraceptives or chemical vasectomies ... to reduce the growth rate."

Phipps Price tells Dan Noyes, "If they embrace birth control, they would be able to manage populations humanely."

But, the government currently spends less than one-percent of its wild horse budget on fertility control.

$50 million a year, about 65-percent of the budget, goes to storing 44-thousand wild horses in facilities like this one near Susanville where they're up for adoption.

They're fed every day, -- a far different life than freedom on the range where they sometimes run up to 30 miles a day.

Dan Noyes asked, "Normally, how high would the horses go, the wild horses go up that mountain?"

Jeff Fontana answered, "During the summer, they'd be up the top of that mountain."

Now, wild horse advocates are worried a Trump presidency could bring a dangerous change for the mustangs.

Rep. Ryan Zinke, Montana Republican testified, "Clearly the present policy is a disaster."

Congressman Zinke from Montana is the president's nominee to head the Interior Department, overseeing the BLM and the wild horse program. As a state lawmaker in 2009, Zinke promoted a bill to kill horses for food.

He testified in Montana 2009, "It's a slaughter house for horses that are either abandoned or old or broke from the livestock point of view."

The I-Team asked if Zinke would now favor slaughtering wild horses held in government corrals. His office said Zinke would not comment during his transition to interior secretary.

Dan Noyes reported in 1989 for World News Tonight, "With the flick of a finger, another wild horse is on its way to the meat packer. ... Thousands each year wind up in slaughterhouses, to be exported for human consumption in countries like France where horse meat is popular."

Just last year, a BLM advisory panel recommended changing policy and allowing wild horses to be sold to slaughter.

Now, the Trump administration tells Dan Noyes, they have "no plan to move forward" with that. "We are evaluating the best path forward for the health and well-being of the federal horse and burro herd and will follow the highest ethical standards consistent with federal law."

Phipps Price tells the I-Team, "And what I don't want to see is for them to just throw up their hands and say, 'Well, we have made a mess of it, so now we'll just have to slaughter the horses in holding.'"

Dan Noyes told the BLM, "We've been doing the same things for decades and it hasn't gotten better."
Jeff Fontana answered, "Well, I certainly don't have the answer, but there's a lot of people working on answers to the problem."

You can adopt a wild horse for only $125, but of course, caring for one will cost much more over the years. Adoptions are way down from what they once were, making this problem all the more pressing.

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I-Team investigates wild horse program: What does Trump presidency mean for their future?

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The White House is responding to an I-Team investigation into wild horses. They are protected under federal law as "living symbols" of the nation's pioneer spirit.

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Communication at the heart of change explains the essential role that information and communication plays in development. Sustainable development demands that people participate in the debates and decisions that affect their lives. They need to be able to receive information, but also to make their voices heard.

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Spanish RE introduction to the new world

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Spanish RE introduction to the new world

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by Elliott West

For all the calamities that came in the long run, European contact at first offered American Indian peoples many opportunities and advantages. Old World technologies provided a range of trade goods that brought vast improvements to everyday life. Iron pots lasted virtually forever. Compared to a fish hook whittled from bone, a metal hook seemed a miracle. Woolen blankets were lighter than animal hides and served better in keeping a body warm.

What was arguably the greatest contribution, however, was not made of metal but of flesh and blood-the horse. Its effects, especially on western tribes, were truly revolutionary. It altered their material lives, rearranged their relations with their environments, and fed a burst of power and affluence. Ironically, over time horses contributed also to American Indians' mounting difficulties as the tide of white settlement rolled over them.

When Spanish explorers rode into the West in the 1540s, their horses were, in a sense, coming home. They were native to the Great Plains, descendants of the collie-sized hyracotherium that appeared more than thirty million years ago, but like dozens of other species, horses had gone extinct in the New World about ten thousand years ago at the end of the last ice age. Before that, however, some had crossed the exposed bridge of land that once connected today's Alaska with Siberia, and as their cousins vanished in the Americas, they survived and flourished in central Asia, the largest grassland on earth.

Roughly five thousand years ago people on that vast pasture first domesticated horses, and the first horse culture-that is, a way of life centered on the animal's gifts and possibilities-was born. Life on horseback offered enormous advantages in trade, hunting, and especially warfare, and beginning with the peoples of central Asia, most horse cultures would turn to conquest, and most peoples conquered by them would in turn adopt the horse and its expansive life. Thus horse cultures spread to China, the Middle East, North Africa, and Europe.

Among the most successful was that of the Spanish, who developed a superb equestrian military tradition. After 1492 that horseback prowess was turned to the conquest of the Caribbean, South America, and Mexico. From there conquistadors led columns of horsemen northward into present-day Arizona and New Mexico and from there onto the Great Plains. With that, the horse had come home, completing a ten-thousand-year circumnavigation of the world.

In a sense, however, it was not the same animal at all. Horses had left their birthplace wild. They returned in cultural partnership with humans. The American Indians whose distant ancestors had hunted and eaten horses millennia before now saw them as living tools offering to expand their lives in ways none could have imagined. In time that dawning dream of possibilities would spread across the West and transform the lives of tens of thousands of Native peoples.

There was a lag between the horse's homecoming and its spread, however. Spanish colonizers, concentrated in the Rio Grande valley of New Mexico, well knew that their horses were a key to their control, and so they kept them, quite literally, on a tight rein. Only in 1680, when Pueblo Indians rose up and overwhelmed their Spanish overlords and drove them out of northern New Mexico for a dozen years, did Indians gain access to the Spanish herds. Once they did, horses and the horse culture expanded at a breathtaking pace. Horses were traded and stolen from one tribe to another. By 1700 the tribes of the Great Basin had them, and thirty years later those of the northern Rocky Mountains. By around 1780, a mere century after it had begun, the spread of the horse culture across the West was complete, and peoples from the Columbia River basin to the Great Plains were reshaping their lives and redreaming their futures according to its promises.

Astride horses, American Indians could hunt far more effectively in many parts of the West, especially among the vast herds of bison on the Great Plains. Those bison were hunted not just for their meat but also their hides, which women processed into robes to feed a hungry market in the east and Europe. Horses thus expanded Native trade and brought a flow of new items into their lives-a trade invigorated also because Indians could travel so much farther and faster than before. As from the time of the first horse cultures in central Asia, western Indians exploited a new military potential. Some groups quickly developed astonishing skills as mounted warriors and proceeded to expand their hunting and trading territories against weaker neighbors. Less apparent were changes in Indians' perceptions of the world and its possibilities. As they adapted their lives to horses and all they offered, they felt what others must have over the millennia, a burst of confidence, empowerment, and freedom. Referring to his people, the Kiowas, the writer N. Scott Momaday put it this way: "They became centaurs of the spirit."

At the root of this flowering of opportunity was a fundamental realignment of people and their environment. The West, and any place on earth, can be imagined as a vast reservoir of energy waiting to be tapped. All of that energy comes from the sun, all life relies on it. It takes many forms. Plants such as trees and grasses absorb and transform solar energy. Some animals, herbivores, then eat plants to make that energy their own, and in turn other animals, carnivores, eat those animals. Thus the sun's energy flows through and among all living things (and much is stored in things long dead, like coal, oil, and natural gas).

In each step of that movement, however, most of the sun's energy is lost. Plants lose about 90 percent of what they take in and transform. A cow or a deer or a bison in turn loses 90 percent more when it eats grasses or shrubs, and people eating one of those herbivores lose 90 percent of that. In this "energy pyramid," then, available power declines sharply as it moves through the food chain. A man eating a bison steak was acquiring only .1 percent, or one thousandth, of the original solar energy making its way through the system.

Much of the West, like the Asian steppes where the horse culture first arose, is a vast grassland, one of the planet's largest. People, however, were unable to tap directly into most of that enormous pool of solar energy. They had to wait for others-bison, deer, elk, pronghorns, or other grazers-to do so before they could take their turn. A horse, as a herbivore, gets its power by eating grasses. By leaping onto the back of a domesticated horse and guiding it to his purposes, whether hunting or trading or making war, a man in effect was moving one step down the energy pyramid. With that leap, suddenly he had direct access to the energy of grasses. He effectively expanded his potential power ten times over.

That was the essence of the horse culture. It spanned what had always been an unbridgeable gap in people's ability to tap into the energy around them. In effect it transformed a mounted Sioux or Comanche or Nez Perce man into a new creature, one with the brain and imagination of a human and the grass-fed power, speed, and grace of a horse. As Momaday wrote, such a person had become one of those mythical creatures, a centaur, half-man and half-stallion.

And like those mythical beasts, horseback Indians flexed their new power and put it into play in the world around them. One result was a boom in population on western grasslands. Nearly all tribes that whites encountered on the Great Plains-Comanches, Lakota Sioux, Cheyennes, Kiowas, Crows, Blackfeet, and others-migrated there during the era of horses, drawn by the new access to energy and power. With the benefits of expanding trade, they enjoyed an unprecedented affluence. Peoples from the Plains to the Columbia plateau lived in far larger tipis, lodges they now could move with the help of horses. Inside such a lodge might be an array of items, everything from New England firearms and English blankets to carpets and coffee grinders, purchased with the fruits of a new hunting prowess. The goods were daily reminders of how, via the horse, American Indians were plugged into a global economy and had far easier access to traditional trade with other tribes.

Some groups took fuller advantage than others, which resulted in a dramatic shifting of power across the West. With thousands of forbidding horseback warriors, Comanches created the largest Indian empire in North American history, stretching from the central Great Plains deep into Mexico. The Lakota Sioux and Cheyennes dominated the northern Plains and warred with the Blackfeet, Crows, and others over neighboring regions. On the Columbia Plateau the Nez Perces used their huge horse herds to range over hundreds of miles and to funnel trade from the Pacific coast to today's North Dakota. For every winner, of course, there were losers. Village-dwelling groups, like the Pawnees and Mandans on the Missouri River and the Pueblos on the Rio Grande, suffered terrible raids from mounted enemies.

There were costs even for the winners. The quickening warfare over control of prime territories took an awful toll among warriors. By one census Cheyenne women outnumbered men three-to-two. The enormous herds needed to sustain a horse culture, numbering several animals for every man, woman, and child, soon had an alarmingly corrosive impact on streamside ecologies where many American Indians had to spend their winters, leaving fewer and fewer sanctuaries during those desperate, storm-wracked months. Although other factors were involved, the prodigious hunting by horseback contributed to a dramatic decline in the number of bison, the animal essential for survival, especially on the Plains.

The enhanced connections to the wider world brought more than abundant goods. It likely was no coincidence that the first time smallpox swept across the West was in 1780, when the horse culture was in place and the virus could spread from people to people, from New Mexico to Puget Sound, during its short window of contagion. Even the vigorous flow of new goods had its downside. American Indians' growing reliance on metal goods, firearms, and other items they could not make for themselves left them increasingly vulnerable to the outsiders who supplied them.

The far graver vulnerability was the partnership with the horse itself. The West, birthplace of the horse, in the end was the last place where the horse culture rose and flourished. Its reign was brief. After barely a century the westward roll of white society, with its irresistible numbers and its revolutionary technologies, including that of the railroad, undercut and overwhelmed the way of life that had brought unprecedented power, affluence, and glory to dozens of Indian peoples of the American West.

Elliott West is Alumni Distinguished Professor of History at the University of Arkansas. He is author of, among other books, The Contested Plains: Indians, Goldseekers, and the Rush to Colorado (1998), The Way to the West: Essays on the Central Plains and, most recently, The Last Indian War: The Nez Perce Story (2009).

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by Elliott West For all the calamities that came in the long run, European contact at first offered American Indian peoples many opportunities and advantages. Old World technologies provided a range of trade goods that brought vast improvements to everyday life. Iron pots lasted virtually forever.

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Knighthood as we know it probably began around the year 800. Knights were an important element of feudalism, a pyramid of power, with God at the top, the king under him, lords and barons under the king, and at the bottom , the numerous serfs who did the labor. Males above the serf class were expected to perform military service as a knight.
When the Normans defeated the English in 1066 and took over Britain, they brought their system of feudalism with them. Knights would protect the interests of their lords in exchange for money or land.

A mounted knight, covered with armor and mounted on a sturdy steed, was considered the ultimate fighting machine at the time. The knight's body was almost completely protected with metal plates held together with screws, straps, buckles, and hinges that could weigh well over 100 pounds in all.
Good war horses were in great demand and were very expensive. The horse had to be strong enough to carry the armored knight long distances and be capable of maneuvering in battle with quick attacks. It also had to be bold and courageous, willing to plunge headlong into the confusion and violence of war.
So what breed of horse was this indomitable destrier? Equine historians have debated this topic for years. Some believe the war horses were huge beasts standing 18 hands tall, ancestors of breeds like the Shire, Belgian, and Percheron. More recent evidence, however, suggests that the medieval war horses were of average height - 14 or 15 hands, and while they were certainly stout and muscular, they didn't have nearly the girth of a modern draft horse.
How do they know this? Saddles, armor, and other items the horses wore have been measured and compared with modern equine equipment. The old fittings indicate that these legendary steeds were about the same size as the modern stock horse, perhaps comparable to a muscular Quarter Horse of foundation breeding.
The modern horse breeds that best fit the descriptions of the ancient war horse of Europe are the Friesian, the Holstein, and the Norman. A sub-breed of the Norman, the Norman Cob, is most likely the closest descendant of the mount the knight rode into battle.
How did a more or less average-sized horse carry a knight and his heavy armor? Humans in Europe were much smaller during the Middle Ages than they are today. The average man was only about 5'3" and weighed about 120 pounds. Add 100 pounds of armor to that, and you get 220 pounds. A short, stocky horse of average height, with good bone and muscling, would have no problem carrying the weight. A horse can fairly easily carry 20% of its own weight. If these chargers weighed 1,200 pounds, a burden of 220 pounds would certainly not be too much for them to bear.
We may never know exactly what breed the knights rode, or what modern breeds carry their bloodlines. From the evidence that has been recovered, however, along with the weight theory, we know that the animals were probably not the ancestors of our modern draft giants.

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Knighthood as we know it probably began around the year 800. Knights were an important element of feudalism, a pyramid of power, with God at the top, the king

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Top Documentary Films: The Barbarian Mongols

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Top Documentary Films: The Barbarian Mongols The Mongols have always been nomads, though they have always cultivated plants. They moved every season with their camps and livestock, from one pasture to another. In the 13th century, the Mongols together with the Turks captured Eastern and Central Anatolia.

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Horses and the Persions Empires royal roads

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Horses and the Persions Empires royal roads

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The Royal Road (Circa 450 BCE - 420 BCE) : HistoryofInformation.com

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"The postal system during the reign of Xerxes I is also described in the Biblical Book of Esther. While the historical details of the Book of Esther are difficult to verify, it would appear that a swift messenger system connecting all provinces of the Persian Empire was at the disposal of the ruler.

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The chariot was a light vehicle, usually on two wheels, drawn by one or more horses, often carrying two standing persons, a driver and a fighter using bow-and-arrow or javelins. The chariot was the supreme military weapon in Eurasia roughly from 1700 BCE to 500 BCE but was also used for hunting purposes and in sporting contests such as the Olympic Games and in the Roman Circus Maximus.

Horses were not used for transport, ploughing, warfare or any other practical human activity until quite late in history, and the chariot was the first such application. Donkeys and other animals were preferred in early civilizations.

The Horse

The horse's main ecological niche was the Eurasian steppe; a very wide (4,800 km) and narrow (800 km on average) strip of grassland running roughly from Hungary to China, encompasing parts of what today is Ukrania, southern Russia, Kazakhstan, Uzbekistan, Turkmenistan, Kyrgyztan, Tajikistan and Mongolia. For most of ancient history, the steppe --which means "wasteland" in Russian-- was the home of nomadic societies whose economy was based on herding, complemented by hunting and, to a much lesser degree, sporadic, itinerant agriculture. No cities or settled communities existed in the steppe, save a very few spots.

Steppe dwellers domesticated the horse for the purpose of breeding it for food like sheep and other animals already domesticated. That process is unfortunately poorly understood, and it occurred sometime before 2500 BCE. The wheel, an invention imported from the civilized Middle East, had arrived in the steppe around 3100 BCE. The invention of the chariot in the steppe - perhaps originally meant as an improved tool for hunting - occurred roughly by 2000 BCE, probably in the area just east of the southern Ural mountains, where the oldest chariots have been unearthed. The word for horse appears just around this date for the first time in Mesopotamia, when an increase in north-south trade through Iran is attested.

Arrows and javelins were the main weapons used by the fighter on board, while a second person drove the chariot.

Invention of the Chariot

The chariot then became a moving platform from which soldiers could shoot at enemies. Arrows and javelins were the main weapons used by the fighter on board, while a second person drove the chariot. The tactic was to move constantly, in and out of the battle, shooting from a distance.

There is no clear explanation as to why humans invented the chariot first, before riding the horse directly, which seem more straight-forward to us. A chariot was obviously more expensive than the horse alone, and chariots could not enter or properly manoeuver in landscapes where a mounted horse can, such as hills, marshes or forests. We know people tried mounting horses very early, since we have found drawings depicting it, but those seem rare experiments that did not seem to work. The most common scholarly suggestion is that horses at that time were weaker than in the present, unsuitable for supportingng a man and only after a very long period of constant, selective breeding, did a stronger horse come into being. Horses started consistently to be mounted roughly a millenium and a half after the chariot was invented.

The "compound bow", invented sometime during the second millenium BCE, was the final ingredient for the rise of a deadly ensemble. Bow and arrow were much older, and the innovation of the compound bow was the use of two types of materials, inside and outside the bow, which gave it considerably more power. Compound bows were able to accurately hit a target 300 m away, and penetrate an armour 100 m away. It was the preferred weapon of charioteers and later horseback riding societies. Its power is reflected in the fact that these bows were last used in war as recently as the 19th century CE by the Chinese, well into the fire arms age.

We have scarce knowledge of what happened with the communities in the steppe once the chariot was invented. We can assume that war intensified - and some evidence about it does exist -, and those who first or better grasped the new invention stormed their neighbours, sizing valuable hunting and pasturing land rights. We truly understand the impact of the chariot only when this new form of warfare came out of the steppes and into the settled, agricultural, civilized lands.

Charioteers & Warfare

The first reference to charioteers in the civilized world comes from Syria around 1800 BCE. Over the course of the next four centuries, chariots advanced into civilization, either by direct migration of steppe people or by diffusion, and it quickly came to be the preferred elite weapon.

Hittites established their first kingdom with the help of chariots c. 1700 BCE, and thereafter used them intensely; Hurrians, from somewhere near the Caucasus, penetrated in the Middle East and carved a kingdom for themselves that was to play an important role in that region, Mitanni, around 1500 BCE; Egypt's north was taken by charioteers called Hyksos c.1650 BCE, who established their own dynasties; in China the first dynasty appeared, the Shang (starting c. 1600 BCE), with an aristocracy of charioteers; Mycenaeans adopted the chariot in Greece, which likely helped them invade their more sophisticated Minoan neighbours (c. 1400 BCE); tribes called Kassites appeared driving chariots from Iran and took Babylonia, establishing their own dyansty (c. 1570 BCE), which was to last four centuries; and the steppe dwelling Aryans, charioteers as well, from c. 1500 BCE migrated south to what today is Iran, Pakistan and India, profoundly influencing the local culture, particularly establishing the basis for Hinduism. The famous king Darius the Great of the much later Persian empire would proudly state his Aryan descent for good reason.

Everywhere, in Europe, the Middle East, India and China, all rulers, from petty chiefs to great pharaohs, took the chariot as their master weapon. They started depicting themselves riding chariots, waging wars in chariots, including chariots and horses in their tombs as symbols of power, and so on. Their surrounding aristocracy of course followed suit, so the elite forces in every polity came to be charioteers. The horse came to be a valuable military asset, no longer a food source. Horse breeding became key for these states, and all powerful kings aspired to have the proper stables to supply their armies with chariots; imports from the steppes, though, long remained their major source.

The most famous chariot battle was that of Kadesh (1294 BCE), fought between the two super powers of the time, Egypt and Hatti (Hittites), where some 50 chariots are presumed to have participated for each side. The small number of chariots compared to infantry troops is a good indicator of how effective the chariot was: in China the ratio was up to 25 infantry soldiers per chariot.

Decline in Use

The use of the chariot declined very slowly, starting around 500 BCE (and yet, in some parts of Europe the technology was just arriving at that time). First and probably foremost, because horseback riding was developed in the steppes, and slowly but surely replaced the need for chariots. The first known forces mounting horses were those of the Scynthians, steppe people who in the 7th century BCE attacked the Assyrian empire on horseback. Second, because infantry, formerly helpless against chariots, became more sophisticated due to the expanding use of iron weapons (from c. 1200 BCE onwards), and to new tactics in the form of phalanx formations. Fighting the invading Romans, the Celts were probably the last people who used chariots extensively, until around the 4th century CE.

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The chariot was a light vehicle, usually on two wheels, drawn by one or more horses, often carrying two standing persons, a driver and a fighter using bow-and-arrow or javelins. The chariot was the supreme military weapon in Eurasia roughly from 1700 BCE to 500 BCE but was also used for hunting purposes and in sporting contests such as the Olympic Games and in the Roman Circus Maximus.

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The Dordogne, France: Lascaux's Prehistoric Cave Paintings - Rick Steves’ Europe Travel Guide

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Horses and other large mammals who lived on Alaska's massive northern slope during the last ice age relied on the land bridge across what is now the Bering Strait to cope with the rapid climate changes that characterized the period, according to researchers.

It allowed them to move between different continental habitats during what the study team described as boom and bust cycles.

Short periods of warm climate during the last ice age triggered these boom-and-bust cycles in the populations of large mammals in the Arctic, the researchers reported in the Proceedings of the National Academy of Sciences.

Many large mammals became extinct when these cycles and the ice age ended and spreading peatlands and rising sea levels restricted the animals' ability to move between continents.

Scientists from the University of Alaska Fairbanks and the University of California examined the age and abundance of the bones of megafauna - a term for mammals weighing more than 100 pounds - on Alaska's North Slope, a tundra region between the Brooks Range and the Arctic Ocean.

By radiocarbon dating the fossils and comparing their ages and abundances to climate records spanning the past 40,000 years, the researchers reconstructed a picture of what happened to horses, woolly mammoths, steppe bison and other mammals in Alaska's Arctic.

"We wanted to know how these large animals responded to the rapid climatic changes that characterized that period of Earth's history," said lead author Daniel Mann, an associate professor in the Department of Geosciences at the University of Alaska Fairbanks.

To do this, the study team tested a hypothesis suggested by retired paleontologist Dale Guthrie that megafaunal populations experienced boom-and-bust cycles during the ice age as the vegetation tracked climate change.

The last ice age, which began about 80,000 years ago and ended around 12,000 years ago, was a time of diverse climates, Mann said.

The results of the 20-year study show that animal and plant communities were much more changeable during the ice age than they have been during the last 12,000 years of interglacial climate in which we live today.

"This has been a long-term effort, and it has resulted in a much larger data set of bones from one given area than anybody else has ever compiled," said co-author Groves, a wildlife biologist with the university's Institute of Arctic Biology.

During the last ice age, a lowered sea level drained the Bering Strait, the narrow seaway now separating Alaska and Asia.

Being able to move back and forth across Bering Strait was probably what kept the large Arctic mammals thriving for so long, Mann said. This travel corridor allowed mammals to come to Alaska when their favored foods - grasses, sedges, and rushes - thrived during warm periods.

The corridor also allowed mammals to leave Alaska for greener pastures when prolonged periods of warmer, wetter climate allowed peat to spread, which cooled the ground and discouraged the grass, sedges and rushes from growing.

"Counterintuitively, rapid climate changes during the ice age were, at times, highly beneficial for megafauna when rapid warming allowed grasses and forbs to briefly spread before peatlands had a chance to take over the landscape and degrade forage quality," Groves said.

When the planet's big ice sheets collapsed at the end of the last ice age, their melting caused global sea levels to rise as much as 100 meters in roughly 10,000 years, which is fast in geological time, Mann noted.

"In the case of northern Alaska, the rising seas flooded the Bering Strait, which changed the climate of the North Slope," Mann said.

"Summers became wetter and cooler because the sea was much closer. This encouraged the spread of organic soils and peat at the same time that it cut off access between Asia and Alaska."

The animals could not migrate elsewhere because ice sheets were still blocking their way to the east.

Mann became interested in the study when he and other researchers went to archaeological sites on the North Slope in 1994 to see what ice-age humans were eating.

He said they did not find much evidence of humans on the North Slope, which suggested they weren't a driving factor in the mass extinction of the large mammals.

However, the researchers did find more than 4000 bones of ancient ice-age animals during the last two decades. The bones are now archived in the University of Alaska Museum of the North.

It took two decades to collect enough bones for the study and then several more years to figure out the statistical methods needed to analyze the radiocarbon data, Mann said.

Groves continued: "One of the contributions of research like this is helping humans understand the challenges large animals face today from climate change. It's a testimony to the value of doing long-term research."

Evolutionary biologist Beth Shapiro, of the University of California Santa Cruz, who was also a part of the study, said: "We've known for some time that the population sizes of these animals fluctuated throughout the last ice age. What this study provides is a possible explanation for these changes."

The study's conclusions have implications for present-day extinctions.

Sharpiro said: "As human populations grow, patches of suitable habitat for many species are becoming increasingly isolated from each other. If we are to preserve these species, we will need to devise strategies that allow these populations to remain somehow connected."

Mann says Arctic climates are particularly unstable and are changing rapidly today. "This means the Arctic is an interesting place to study how climate changes cause extinctions, and the past gives us many interesting examples of extinction there. Plus, bones are exceptionally well-preserved because of the frozen ground."

Based on current evidence, the regional extinction of the ice-age megafauna was complete in arctic Alaska around 12,000 years ago, leaving caribou, the tundra muskox, and brown bears as the only surviving megafaunal species.

Of the Pleistocene species, horses and steppe bison survived the longest. The most recent horse lived between 12,400 and 12,700 years ago. They said there was no direct paleontological evidence in the form of dated bones in mainland Alaska supporting claims based on ancient DNA that mammoths and horses survived as recently as 7500 years ago.

Their research pinpointed a surge in horse numbers on the North Slope of Alaska from around 40,000 years ago during these boom and bust cycles.

The project was supported by the National Science Foundation and the US Bureau of Land Management.

Life and extinction of megafauna in the ice-age Arctic
Daniel H. Mann, Pamela Groves, Richard E. Reanier, Benjamin V. Gaglioti, Michael L. Kunz, and Beth Shapiro.
doi: 10.1073/pnas.1516573112

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Land bridge helped ice-age horses and other mammals survive for millennia - Horsetalk.co.nz

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Horses and other large mammals who lived on Alaska's massive northern slope during the last ice age relied on the land bridge across what is now the Bering Strait to cope with the rapid climate changes that characterized the period, according to researchers.

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Evolution explained in an animation about the horse

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Created for schools, this animation explains evolution by looking at the ancestry of the horse Check out our other videos: Mary Anning https://youtu.be/Of5sK8p2rZY Galileo https://youtu.be/REUdlA44vuY A brief history of life on earth https://www.youtube.com/watch?v=0B3IuFEVpN4