African pygmy mouse

The African pygmy mouse (Mus minutoides) is one of the smallest rodents in the world. An adult averages about 50 mm in body length, with a tail of about 40 mm, and weighs around 5 g. Its coat is grey to brick-red above and paler underneath, and its ears are small but prominent and triangular. The species is widespread across sub-Saharan Africa, where it lives in colonies or in pairs in grass close to water and is an excellent climber. It belongs to the superfamily Muroidea, the same enormous group as the house mouse, and forms a superspecies complex with Mus musculoides. Females reach breeding age at about six to eight weeks, pregnancy lasts around twenty days, and a litter of about three young is born blind and hairless; the eyes open after two weeks and weaning is complete after three. Lifespan is about two years, though captives have been reported to live beyond four. The mouse stacks pebbles in front of its burrow, which gather dew overnight so it can drink them in the morning, and its sex determination is unusual, since rearrangements of the X chromosome make many XY individuals female. It is also kept as a pet in other parts of the world, in pairs or small colonies.