Horses transformed warfare.
Horses allowed Native nations to better defend themselves, as settlers and soldiers encroached on tribal lands. Attacks by the U.S. Cavalry and vigilante groups forced tribes to polish their attack strategies. Horses made fighters swift in battle and became comrades in arms.
But the horse was also a factor in conflict between tribes, as various groups migrated or sought to expand their hunting territories. Old tribal alliances shifted. Tribes that were poor in horses raided their neighbors’ herds to increase their own.