Massive.

The Transcontinental Railroad made Sheridan’s strategy of “total war” [on Native populations] much more effective. In the mid-19th century, it was estimated that 30 milion to 60 million buffalo roamed the plains. In massive and majestic herds, they rumbled by the hundreds of thousands, creating the sound that earned them the nickname “Thunder of the Plains.” The bison’s lifespan of 25 years, rapid reproduction and resiliency in their environment enabled the species to flourish, as Native Americans were careful not to overhunt, and even men like William “Buffalo Bill” Cody, who was hired by the Kansas Pacific Railroad to hunt the bison to feed thousands of rail laborers for years, could not make much of a dent in the buffalo population. In mid-century, trappers who had depleted the beaver populations of the Midwest began trading in buffalo robes and tongues; an estimated 200,000 buffalo were killed annually. Then the completion of the Transcontinental Railroad accelerated the decimation of the species.

Massive hunting parties began to arrive in the West by train, with thousands of men packing .50 caliber rifles, and leaving a trail of buffalo carnage in their wake. Unlike the Native Americans or Buffalo Bill, who killed for food, clothing and shelter, the hunters from the East killed mostly for sport. Native Americans looked on with horror as landscapes and prairies were littered with rotting buffalo carcasses. The railroads began to advertise excursions for “hunting by rail,” where trains encountered massive herds alongside or crossing the tracks. Hundreds of men aboard the trains climbed to the roofs and took aim, or fired from their windows, leaving countless 1,500-pound animals where they died.

Harper’s Weekly described these hunting excursions:

Nearly every railroad train which leaves or arrives at Fort Hays on the Kansas Pacific Railroad has its race with these herds of buffalo; and a most interesting and exciting scene is the result. The train is “slowed” to a rate of speed about equal to that of the herd; the passengers get out fire-arms which are provided for the defense of the train against the Indians, and open from the windows and platforms of the cars a fire that resembles a brisk skirmish. Frequently a young bull will turn at bay for a moment. His exhibition of courage is generally his death-warrant, for the whole fire of the train is turned upon him, either killing him or some member of the herd in his immediate vicinity.

Hunters began killing buffalo by the hundreds of thousands in the winter months. One hunter, Orlando Brown brought down nearly 6,000 buffalo by himself and lost hearing in one ear from the constant firing of his .50 caliber rifle. The Texas legislature, sensing the buffalo were in danger of being wiped out, proposed a bill to protect the species. General Sheridan opposed it, stating, ”These men have done more in the last two years, and will do more in the next year, to settle the vexed Indian question, than the entire regular army has done in the last forty years. They are destroying the Indians’ commissary. And it is a well known fact that an army losing its base of supplies is placed at a great disadvantage. Send them powder and lead, if you will; but for a lasting peace, let them kill, skin and sell until the buffaloes are exterminated. Then your prairies can be covered with speckled cattle.”

Read the rest at The Smithsonian.