Bassen is a District in the municipality Oyten in Lower Saxony. The place is about 20 km east of the city center of Bremen and about 100 km southwest of Hamburg. In the northern area the Wümme flows through Bassen.

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 highlands of northern 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, gray 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).