Other terrestrial rats are considerably smaller and mostly have tails that are longer than their head-and-body lengths.

[1] The range of Tome's spiny rat extends from southeastern Honduras to southwestern Ecuador and possibly to northern Peru.

It is a common species in evergreen and deciduous forest, favouring riparian corridors and low-lying areas.

During the day it may hide in a burrow or under a fallen tree, in a hollow log or in dense vegetation.

It feeds on fruits and seeds, fungi, plant material and insects, carrying larger objects to a safe place before consuming them.

[5] Morphological characters and mitochondrial cytochrome b DNA sequences showed that P. semispinosus belongs to the so-called semispinosus group of Proechimys species, and shares closer phylogenetic affinities with the other member of this clade: P.