Instead, they can most readily be distinguished by the presence of a gall bladder in A. cursor (absent in the montane species), by karyotypic analysis, or by means of PCR based techniques.

It is definitively known to inhabit eastern Brazil from Paraíba to Paraná, where it lives in patches of tropical Atlantic Forest and restinga scrubland at elevations from sea level to 1,170 metres (3,840 ft).

[7] These latter sources lack a definitive genetic analysis of the individuals identified, and it has been argued that they may represent members of other species, such as the montane grass mouse.

[11] Although the size of their home ranges does not change, the population density of cursor grass mice becomes significantly higher during the rainy season, when insects are most abundant.

Pregnant females construct globular nests, and give birth to a litter of two to nine young, with an average of four, after a gestation period of 23 days.