Table of contents for The Story of Yellowstone

Chapter One: The Big Bang, Earth’s Fiery Birth and the Origins of Life

The origins of the universe, our solar system and Earth are presented as background information for Yellowstone’s story. Several themes from our planet’s early history find modern counterparts in the park today, including the extraordinary volcanism from both eras and the similarity between Earth’s original lifeforms and microbes found in the park’s thermal areas. The chapter also describes the formation of the tectonic plates and how Yellowstone has drifted along the North American Plate for billions of years, most recently from south of the equator to its current location. And it tracks the evolution of life following the Cambrian Explosion that eventually yielded fish, amphibians and then reptiles, the latter of which came to dominate Earth during the dinosaur era.

Chapter Two: Dinosaurs Rule

About 250 million years ago, widespread volcanic activity greatly heated Earth, leading to a mass die off of 90 percent of all life on land and in the oceans. This mass extinction led to the evolution of dinosaurs and other large reptiles, which became the masters of the land, skies and seas. Long-necked dinosaurs, the largest animals ever to walk the Earth, plodded through the lush Yellowstone landscape during some of this time. And the long-necked plesiosaurs hunted in the shallow seas that periodically covered the area, while pterosaurs fished and hunted from the skies above. At the end of the era, the familiar T. rex and triceratops lived in Yellowstone—until an enormous asteroid slammed into the Yucatán Peninsula and ended their rule.

Chapter Three: The Age of Mammals

Small mammals lived in the shadows of the dinosaurs until the asteroid hit. After that, mammals diversified, grew larger and took charge on land. Perhaps the most charismatic group of mammals to inhabit Yellowstone lived during the ice ages. This included mammoths, mastodons, camels, horses, ground sloths, American lions, cheetahs, saber-toothed cats, giant short-faced bears and dire wolves. Three of every four ice age mammals died out by 10,000 years ago, but the animals that persisted live on in Yellowstone today, including grizzly bears, gray wolves, cougars, elk, bison, moose, pronghorn antelope and bighorn sheep.

Chapter Four: Mountains Rising

Late in the dinosaurs’ reign, the flat Yellowstone landscape began rising to the west. And after the dinosaurs disappeared, volcanos similar to Mount St. Helens came to dominate the park’s landscape with each one erupting every few hundred to a few thousand years apart. Cascading mud, ash and grit from these eruptions buried trees in the valleys below, creating the petrified forests revealed by erosion today. By the end of this mountain-building period, Yellowstone and the surrounding lands lay covered in crumbly rock and soil to nearly a mile deep in places. Only the highest peaks in the park jutted above these millions of acres of volcanic debris, covered thickly by forests and coursed here and there by meandering streams.

Chapter Five: The Yellowstone Supervolcano

A little more than 2 million years ago, one of Earth’s greatest explosions rocked ancient Yellowstone. That blast, its speeding waves of hellish lava and its skyrocketing column of ash and rock, devastated the area. When the land finally settled, an enormous crater 60 by 40 miles around and 1,000-feet deep smoldered in the spot where mountains once towered. The supervolcano exploded two more times since then and slumbers restlessly beneath the park today. Those catastrophic explosions, the hotspot that fuels them and subsequent lava flows gave form to the unique Yellowstone landscape we see today.

Chapter Six: Icebound

At the height of Yellowstone’s most recent ice age, 25,000 years ago, all but a sliver of Yellowstone lay under 4,000 feet of ice and snow, including most of its mountain peaks. During the previous glaciation, more than 125,000 years earlier, a similar scene played out. The ice ages’ glaciers carved the mountains and valleys seen in and around the park today, and after the ice melted away for good by 13,000 years ago, a rocky, barren landscape remained. In time, pioneering plants, trees and animals established themselves, and today’s familiar Yellowstone began taking shape.

 Chapter Seven: The Big Burn

 Since the extensive fires in 1988, seen by many then as a tragedy, a great deal has been learned about the importance of wildfire in Yellowstone and other natural environments. One thing that researchers discovered from lake-floor core samples is that fire is a common occurrence in the park, dating back 11,000 years—to soon after the last glaciation. They also learned that fires occur more frequently whenever the climate periodically warms, as it’s doing today. Further, they saw that the positive effects of the 1988 fires outweighed the negative ones, and that in general, plants, trees and animals have adapted to fire and, in the case of lodgepole pines, depend on it to seed the next generations of forest.

Chapter Eight: Native Americans and Yellowstone

The ancestors of Native Americans arrived near Yellowstone sometime around the end of its last ice age 13,000 years ago. At the time, ice-age mammals still lived on the North American continent, but as the hunter gatherers spread throughout it, most of the megafauna eventually died out. A warmer, drier climate might have contributed to their demise, but more likely, overhunting by people played a larger role. Yet other species adapted and have persisted to the modern day, most notably bison, which have played a major role in the lives of Native Americans since they arrived on the continent.

They hunted bison in the present-day park and gathered plants, as well as traded with other groups. And for more than 11,000 years, they quarried obsidian and other rock there, as well as conducted spiritual ceremonies and sought the healing powers of thermal areas. This chapter highlights some of those peoples who lived in the area or traveled to it seasonally, including the Sheep Eaters (or Mountain People), the Crow, the Bannock and the Nez Perce. They continued using the Yellowstone area until it became the first national park in 1872. After that, they were no longer welcome. The last major encampments happened during the 126-day, 1,170-mile Flight of the Nez Perce in 1877, when hundreds of people from that tribe spent nearly two weeks in the park evading the U.S. Army.

Today, more than two dozen tribes claim ancestral connections to Yellowstone, and the park now consults with them on several issues, including bison management.

Chapter Nine: The Decimation and Restoration of Wildlife

By the time European-Americans began settling the valleys around Yellowstone in the mid 1800s, they had killed off nearly all the elk, bison, cougars and wolves throughout the eastern United States. They then set their sights on them in the West, as well as on many other species. Tens of millions of bison once ranged throughout the Great Plains states, but by 1900, just 23 wild bison remained in North America, in Yellowstone’s Pelican Valley. Also, before European settlement, an estimated 10 million elk lived throughout the United States, but by 1900, their numbers dwindled to only 10,000, many of which lived in the safety of Yellowstone. Settlers also shot, trapped and poisoned countless wolves, cougars, bears and coyotes. And while a small population of grizzlies found refuge in Yellowstone, the park killed off its wolves and cougars by 1926.

A growing awareness of conservation starting around 1900 saved bison and elk from disappearing. Yellowstone became a refuge and breeding ground for these animals starting then, but not until later did the park stop killing its predators and eventually restore wolves in the 1990s. Wolves quickly reclaimed their role as the park’s apex predator and improved the health of the ecosystem—keeping elk and coyote numbers in check and allowing willow and aspen to regenerate after being overbrowsed by elk for decades. This created new habitat for beavers, moose, songbirds and other species. Grizzlies also benefited from the return of the wolf and are expanding their range outside of Yellowstone.

Chapter Ten: The Threat of the Supervolcano

Imagine a late spring morning in Yellowstone’s Hayden Valley. Scattered herds of bison graze on the rich green grass; a hungry grizzly searches sagebrush for hidden elk calves; geese, pelicans and ducks feed along the Yellowstone River; and wolf pups frolic in the sunshine by their den. Thousands of tourists drive along the road or have stopped to watch the animals. Suddenly, the earth shakes powerfully and then lava explodes from the ground along an oval path dozens of miles wide. The explosion annihilates the wildlife, the people, the valley, the river—and everything in the central area of the park, including Yellowstone Lake, forests, geyser basins, campgrounds, hotels and visitor centers. Gone also is Mt. Washburn, which lost its southern half to the super eruption 640,000 years ago. Such an explosion with its resulting volcanic winter would have severe consequences for all of humanity, not just in the Yellowstone area.

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