Keays's Nephelomys lives on the eastern Andean slopes and has a long tail and ochre to buffy-brown back fur. A pregnant individual with three embryos was recorded in Peru in November.
It is medium-sized, with dense, long back fur colored ochre to buffy ochre grizzled with brown. The tail is longer than the body and is not bicolored in most specimens. The belly is grayish or whitish, rarely yellowish.
A pregnant female with three embryos was caught at Santa Cruz, Peru, in November. Stomachs of specimens from Cusco contained arthropods and plant material.
An extinction-risk assessment has not been added yet.