The fulvous colilargo is a small rodent. A night survey recorded animals moving among ground-level weeds and climbing among the dry leaves of a felled tree.
In typical Mexican samples, the tail averaged about 1.31 times head-and-body length. The French Guianan vouchers were reported as difficult to distinguish from those samples by coat color and texture.
At Paracou, three vouchers were recorded at night in secondary growth: two moving on the ground through sparse weeds and one climbing among dried leaves on a felled tree.
An extinction-risk assessment has not been added yet.