Bison herd grazing at Lamar Valley, known as "America’s Serengeti" for its bountiful wildlife.
Tourists enjoying the boardwalk at Grand Prismatic Spring in the Midway Geyser Basin, Yellowstone’s largest hot spring. It's deeper than a 10-story building and bigger than a football field.
A closer look at the Grand Prismatic Spring. The multicolored layers get their hues from different species of thermophile (heat-loving) bacteria living in the spring. Colorless and yellow thermophiles grow in the hottest water. Orange, brown, and green thermophiles grow in cooler waters.
Thermophiles are too small to be seen with the naked eye, trillions together appear as masses of color. They are nourished by energy and chemical building blocks. They live in near-boiling temperatures in hydrothermal features with the alkalinity of baking soda, or in water so acidic that it can burn holes in clothing.
Morning Glory Pool which has an average temperature of 159.3°F (70.7°C). Hot springs are the most common hydrothermal features in Yellowstone. Their plumbing has no constrictions. Superheated water cools as it reaches the surface, sinks, and is replaced by hotter water from below. This circulation prevents water from reaching the temperature needed to set off an eruption.
Magpie at Mormon Row Historic District in the Grand Teton National Park.
Female ("Cow") Elk. Elk are the most abundant large mammal found in Yellowstone, comprising approximately 85% of winter wolf kills and are an important food for bears, mountain lions, and at least 12 scavenger species, including bald eagles and coyotes.
The Pronghorn is the fastest North American land animal, capable of reaching speeds of up to 60 miles per hour.
Bison are the largest land-dwelling mammal in North America with bulls weighing up to 2,000 pounds. Yellowstone is the only place in the United States where bison have lived continuously since prehistoric times.
Bison are agile, strong swimmers, and can run 35 miles per hour (55 kph). They can jump over objects about 5 feet (1.5 m) high and have excellent hearing, vision, and sense of smell.
The coyote is a common predator in Greater Yellowstone, often seen traveling through open meadows and valleys.
Coyotes are much smaller than wolves, usually around a third of the size.
Cayote with a freshly caught vole.
Cayotes primarily eat voles, mice, rabbits, other small animals, and carrion—and only the very young elk calves in the spring.
Bison crossing traffic jam at Lamar Valley.
Falls at the Grand Canyon of Yellowstone.
T. A. Moulton Barn in the historic Mormon Row with Grand Tetons in the backdrop.
Pre-supermoon at sunset.
Sunset in the Yellowstone valley.
Grand Tetons sunset at Schwabacher Landing with Snake River in the foreground.
Pre-supermoon rising over Lake Yellowstone.