The family Echimyidae is one of the most widely distributed rodent families in the Neotropics. Virtually every tropical lowland forest contains at least one echimyid species, and many areas contain half a dozen or more species. The commonest terrestrial representatives of the family are within the genus Proechimys, and several species such as Proechimys semispinosus (Central American spiny rat) have been the subject of intensive ecological studies (e.g. Adler 1994, 1996; Adler & Beatty 1997, Alberico & Gonzalez 1993, Fleming 1971, Gliwicz 1984, Gonzalez-M. & Alberico 1993). P. semispinosus is often the most abundant rodent throughout its geographic range in Central America and northwestern South America, and its ecology is now fairly well-known.