533.

Western Mediterranean Mouse

Mus spretus

French: Souris sauvage / German: Heckenhausmaus / Spanish: Raton moruno

Other common names: Algerian Mouse, Grassland Mouse

Taxonomy. Mus spretus lLataste, 1883,

north of Hodna, between M’sila and Barika, Oued Magra, Algeria.

Placed in subgenus Mus on morphological grounds by J. T. Marshall in 1977; this has subsequently been supported by various molecular studies, which group it as sister to a cladecontaining M. musculus, M. macedonicus, and M. spicilegus . Monotypic.

Distribution. Portugal, Spain (including Balearic Is), S France, Morocco, N Algeria, Tunisia, and N Libya.

Descriptive notes. Head—body 79-93 mm, tail 47-73 mm, ear 11-15 mm, hindfoot 14-21 mm; weight 7-19 g. The Western Mediterranean Mouse is a rather small rodent with yellow to gray-brown dorsal fur and white or pale gray ventral fur. Tail is shorter (57-93%) than head-body length. Upper incisors are not notched. Karyotype is 2n = 40, NFa = 38.

Habitat. Mainly found in Mediterranean scrub, brush, and grassland, as well as in cultivated fields and olive groves; never in buildings. In Portugal, this species avoids open woodland and pathways, preferring grassland with tall vegetation, and sites where shrubs, brambles, or dead wood provide additional cover. In the Maghreb,it is mainly associated with sparsely wooded areas with ahigh proportion of bare ground; the highest abundances have been observed in agricultural land, while no mice have been found in mature forests, dense maquis and scrubland, or tree plantations.

Food and Feeding. The Western Mediterranean Mouse eats fruits, seeds, and green parts of plants, as well as insects. It is an opportunistic feeder. It may cause damage to crops in North Africa.

Breeding. The Western Mediterranean Mouse shows sexual inactivity during winter in the south of France and Spain, and two peaks of reproduction are observed in spring and at the end of summer. Gestation is about 19-20 days. Litter size is 2-10 (average 5-3). Newborn young are naked and blind; the eyes begin to open at 12-14 days old, and young are weaned during the third week; adult size is reached at 8-9 weeks.

Activity patterns. This terrestrial rodent is nocturnal and crepuscular. It builds complex systems of interdigitating tunnels through the undergrowth and just below the soil surface.

Movements, Home range and Social organization. Daily displacements vary depending on the habitat, sex, age, and season, the average ranging from 27-8 m to 112 m. Less social than the House Mouse ( Mus musculus), and less colonial than the Moundbuilding Mouse ( M. spicilegus), this species has more stable bonds between males and females. Recorded densities are of 3-12 ind/ha. In Portugal, the mean home range size of adult males was 343 m? each male territory overlapped the territory of at least two females, but was separate from those of the other males; males were thus able to maintain large, exclusive home ranges, which they patrol and maintain byaggressive exclusion of intruders.

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Aulagnier & Thévenot (1986), Aulagnier et al. (2009), Auffray et al. (2003), Cassaing & Croset (1985), Cassaing & Isaac (2007), Chevret et al. (2003), Gerbault-Seureau et al. (2015), Gray et al. (1998), Marshall (1977a), Musser & Carleton (2005), Palomo et al. (2009), Quéré & Le Louarn (2011), Shimada et al. (2010), Stoetzel et al. (2010), Suzuki & Aplin (2012).