Circa 1890–1898, the tribal chief "Misketo" signed Treaty 6, formally incorporating three tribes that had settled in the area as one reserve:[3] Thus, the formal English name now found on maps attempts to incorporate all three communities' names, sometimes with the inconsistent use of either hyphens or commas (or both) between them.

By 1931 only one person remained in Lean Man Band, and they merged with Mosquito Grizzly Bear's Head.

On the official Treaty 4 Adhesion document, the Nakoda words "Wica Hostaka" are written by the X of Lean Man.

During this period, as was the case with other bands, Lean Man did not take a reserve but continued to move back and forth across the border.

During the 1877 treaty adhesion meeting at Fort Walsh, some groups were refused permission to sign as they had been receiving annuity payments from the US in Montana.

As had been the case with other bands, this group moved back and forth across the border, with both the Canadian and American authorities trying to stop the cross-border movement.

Treaty Four Gatherings in the Fort Qu'Appelle area reserve a place in their council meetings for the Mosquito Grizzly Bears Head Lean Man Band.