They participated in the Great Sioux War of 1876 and developed into Colonel George Armstrong Custer's "… most loyal and permanent scouts …".

[2]: 13  The experience of the scouts motivates some present-day Arikara people to carry on the tradition and enter military service.

[5]: 11–24  On the northern plains, 700 Yankton, Yanktonai and Lakota people were the first to aid the U.S. Army in an attack on two adjoining Arikara villages in South Dakota in 1823.

[6]: 54  [7]: 78–79  In 1868, Osage scouts found Cheyenne chief Black Kettle's camp, leading to the Battle of Washita River.

[5]: 61 To commanders of the frontier Army, the need for native scouts with special skills not easily found among ordinary soldiers was pressing.

[5]: 59  On August 1, 1866, the "Act to increase and fix the Military Peace Establishment of the United States" came into force, and the Army could now legally enlist a certain number of native scouts, but no more than 1,000 nationwide at any time, as long as needed.

[8]: 52 [2]: 14 Arikara scouts formed part of the forces assigned to protect crews surveying a route from Bismarck, North Dakota to Bozeman, Montana for the Northern Pacific Railway in 1873.

The Dakota had attacked crew members and soldiers the year prior,[12]: 11, 13–14 [11]: 61  despite treaty provisions stipulating that they would allow rail construction "not passing over their reservation".

Bloody Knife took part in the defense, when the Cavalry came under attack in U.S. territory north of the Yellowstone[9]: 1008–1011  near the mouth of the Tongue on August 4.

News reached Fort Abraham Lincoln of a large Lakota war party on its way to attack Like-a-Fishhook Village almost 100 miles outside the Great Sioux Reservation, and General Philip Sheridan made stopping this a priority.

Although he ordered Custer to protect the Arikara "same as white settlers",[1]: 133  the Lakota attacked on June 13 and killed five men along with the Mandan Foolish Head.

[8]: 205 The expedition set off with a number of young Santee Sioux serving as scouts beside the Arikara, and Bloody Knife along with Lean Bear taking lead roles.

Some of the 22 members in the scout group, as recalled by Strikes Two and Bear's Belly, were Enemy Heart, Young Hawk, Goose and Red Horse.

Upon their return, a mounted Lakota tried to take a Santee scout's firearm, but failed and fled, with he or his horse hit by a shot.

[16]: 103 In 1876, the second chief Son of the Star informed a number of Arikara in the Fort Berthold Indian Reservation about an expedition against some Sioux commanded by "Long Hair" or Custer.

[8]: 52  During the Little Bighorn campaign, the 38 [2]: 14 Arikara engaged there worked to protect base camps, and were dispatched as riders, forming a part of the front battle line.

[8]: 63  Skilled hunters like Strikes Two and Goose each earned more than 100 dollars during the expedition by selling specific cuts of game at fixed prices to the soldiers.

[8]: 85  Realizing that a large number of Lakota were somewhere in the Yellowstone area, the field scouts received orders to retreat to this position in case of defeat.

Custer consulted the remaining scouts and assigned their role in a planned attack to drive away as many enemy horses as possible.

Here they were overtaken by the mounted troops and reproached by Custer for going against his orders to disperse the enemy horses and render them on foot prior to a Cavalry charge.

[8]: 95  They, along with Little Sioux, Red Bear and 11 scouts crossed the river south of the Lakota camp along with the troops under Major Reno.

Bloody Knife joined, wearing a black handkerchief with blue stars given him by Custer, and informed Young Hawk and the other scouts that a number of horses had been taken from the enemy.

[8]: 131 As night fell, four scouts carrying a copy of the same message tried to break through the ring of Lakota surrounding Reno Hill, but were turned back.

[8]: 145  Young Hawk led a pony with the wounded Goose on a travois to the steamboat Far West stationed at the mouth of the Little Bighorn River.

[8]: 145 and 147 In September, General George Crook and his men were in dire need of supplies when they followed the trail of a Lakota camp southward to the Black Hills.

Some of the five[22]: 51  The Arikara accompanying Crook started on their way to Fort Abraham Lincoln with a message asking for relief, and carried the urgent telegram to its destination in only three days.