The park is located at the headwaters of the Yellowstone River, from which it takes its historical name. Near the end of the eighteenth century, French trappers named the river "Roche Jaune," which is probably a translation of the Minnetaree name "Mi tsi a-da-zi" (Rock Yellow River). Later, American trappers rendered the French name in English as “Yellow Stone”. On March 1, 1872, President Ulysses S. Grant signed The Act of Dedication into law that created Yellowstone National Park.
The most famous geyser in the park, and perhaps the world, is Old Faithful Geyser, located in Upper Geyser Basin. Castle Geyser, Lion Geyser and Beehive Geyser are in the same basin. The park contains the largest active geyser in the world—Steamboat Geyser in the Norris Geyser Basin. There are 300 geysers in Yellowstone and a total of at least 10,000 geothermal features altogether. Half the geothermal features and two-thirds of the world's geysers are concentrated in Yellowstone.
Yellowstone is widely considered to be the finest megafauna( 巨型土壤动物 ) wildlife habitat in the lower 48 states. There are almost 60 species of mammals in the park, including the endangered gray wolf, the threatened lynx( 猞猁 ), and grizzly bears( 灰熊 ). Other large mammals include the bison (buffalo), black bear, elk( 麋鹿 ), moose, mule deer, mountain goat, pronghorn( 叉角羚 ), bighorn sheep and mountain lion.
Wildfire is a natural part of most ecosystems, and plants found in Yellowstone have adapted in a variety of ways. Lodgepole Pines —the most common tree species in the park— generally have cones that are only opened by the heat of fire. Their seeds are held in place by a tough resin( 树脂 ), and fire assists in melting the resin, allowing the seeds to disperse. Fire clears out dead and down wood, providing fewer obstacles for lodgepole pines to flourish.
Yellowstone climate is greatly influenced by altitude, with lower elevations generally found to be warmer year round. The record high temperature was 37 °C in 1936, while the coldest temperature recorded is -54 °C in 1933. During the summer months of June through early September, daytime highs are normally in the 20 to 25 °C range, while nighttime lows can go to below freezing—especially at higher altitudes. Winter in Yellowstone is very cold with high temperatures usually between zero to -20 to -5 °C) and nighttime temperatures below -20 °Cfor most of the winter.