What cause the retaliation of red cloud and the Sioux Indians?

Sand Creek Massacre of 1864 and due to intruders having endangered the food resources of the Plains tribes.

Explanation:

The retaliation of red cloud and the Sioux Indians was as a result of Sand Creek Massacre of 1864 and due to intruders having endangered the food resources of the Plains tribes.

After gold was discovered in Montana, the U. S. Army built forts across Lakota hunting grounds, which led to the Bozeman Trail. with its connection to the Oregon Trail, results to miners, immigrants, settlers and wagon trains passing directly through the buffalo feeding areas, which led to damaging the food resources of the Plain Tribes.

Hence, Red Cloud, together with Sioux Indians refused to sign a non-aggression treaty which will allow passage across their lands from Fort Laramie to the gold fields of Montana.

Therefore, various attacks were launched in retaliation against U. S army and settlers, whereby the native warriors employed guerilla tactics.