Northern voalavo

The northern voalavo (Voalavo gymnocaudus), also known as the naked-tailed voalavo or simply the voalavo, is a rodent in the family Nesomyidae found in the Northern Highlands of Madagascar. Discovered in 1994 and formally described in 1998, it is the type species of the genus Voalavo; its closest relative is the eastern voalavo of the Central Highlands. DNA sequencing suggests that it may be more closely related to Grandidier's tufted-tailed rat than to other species of the closely related genus Eliurus. The northern voalavo is found at 1,250 to 1,950 m (4,100 to 6,400 ft) above sea level in montane wet and dry forests in the Marojejy and Anjanaharibe-Sud massifs. Nocturnal and solitary, it lives mainly on the ground, but it can climb and probably eats plant matter. Despite having a small range, the species is classified as being of least concern because it lacks obvious threats and much of its range is within protected areas.

The northern voalavo is a small, mouse-like rodent with soft, grey fur that is only slightly darker above than below. The ears are short and rounded. The long tail appears mostly naked and lacks a distinct tuft, which is present in Eliurus. It differs from the eastern voalavo mainly in the values of some measurements. The skull is delicate, with a long, narrow rostrum (front part), narrow interorbital region (between the eyes), and no development of ridges on the braincase. The molars are relatively high-crowned (hypsodont). It has a body mass of 17 to 25.5 g (0.60 to 0.90 oz).