[1] The species is named to honor Clinton Hart Merriam, a biologist who first described several other members of the genus Perognathus, and first elucidated the principle of a "life zone" as a means of characterizing ecological areas with similar plant and animal communities.

It excavates tunnels by digging with its forefeet and pushing soil backwards with its hind feet, spreading the spoil over the surface of the ground.

An entrance to a burrow is often located at the base of a grass tussock or other plant, the roots of which stabilise the earth, and is loosely plugged with soil when the mouse is inside.

[3] The diet consists primarily of seeds which it carries back to its burrow in its cheek pouches and consumes there, leaving a littering of husks on the floor.

[3] In captivity, a Merriam's pocket mouse has lived on a diet of seeds but without water for four years, but the lifespan of wild individuals is shorter and may be in the range of 22 to 33 months.

[3] Merriam's pocket mouse has a wide range including some protected areas and a presumed large total population.