Use of artificial nest boxes by two species of small, arboreal mammals in ecuadorian tropical dry forest

The nest structure of two species of small mammals, <i>Marmosa simonsi</i> and <i>Rhipidomys latimanus</i> were recorded for the first time. Nests were found inside artificial nest boxes in a tropical dry forest remnant ecosystem in Western Ecuador. We described the nests and categorized them as rearing nest, permanent resting nest and transient refuge, depending on their intended use. Artificial nest boxes provide an optimal place for pup rearing and resting for these small mammals. These nest sites can be useful for ecological studies of behavior and habits of elusive, poorly-known mammalian species.