This rat is known only from Fernandina Island in the Galápagos. A survey on the island's western side found it from the coast to the caldera rim, with a mean body mass of about 30 g.
In the 1995 survey, the mean body mass of 21 animals was 30 g. They were reported as smaller than the sympatric N. narboroughi, which averaged 77 g.
On the western survey sites, capture success was highest where vegetation was densest. The researchers suggested a possible link between available plant cover and population density.
An extinction-risk assessment has not been added yet.