Algerian mouse

Its range extends east of the Pyrenees into southern France, where it is found in south-eastern regions around Toulouse and up the Rhone valley to Valence.

[1] It prefers open terrain, avoiding dense forests, and is most commonly found in temperate grassland, arable land, and rural gardens.

[2] Territorial organization and social behavior Male and female adults are frequently captured in the same location, implying a close relationship with their environment.

[4] Although they defend at least the core areas of their ranges from other mice, they are less aggressive than the house mouse, establishing dominance through ritual behavior rather than overt violence.

In April and May, adults surviving from the previous year produce a new generation of mice, then both they and their new offspring breed during the second peak in August to September.

[11] The Algerian mouse is the only known small mammal species not to show an inverted breeding pattern in European southern populations compared with northern ones.

[9] Researchers have explored the mechanism of inverted breeding patterns by testing for differences in spermatogenetic activity between Algerian mice and closely related species.

Male mice captured during the non-breeding season show normal spermatogenesis and spermiogenesis even though they undergo a reduction in testicular mass and seminiferous tubule diameter.

Sexually inactive male Algerian mice maintain almost normal spermatogenic activity and an intact blood-testis barrier despite a significant reduction of androgenic function.

[citation needed] In laboratory conditions, male mice show care for their offspring, including gathering and protecting their young and sharing nests.

[6] Biologist Michael Kohn of Rice University in Houston, Texas and his associate believed that they "caught evolution in the act" while studying mice resistant to warfarin in a German bakery.

Genetic study revealed that the supposed house mice, Mus musculus, carried a significant amount of Algerian mouse DNA in their chromosomes and a gene (VKOR, which has been thought to appear first in Mus spretus and perpetuate because it has helped the mice to survive while eating vitamin K-deficient diets) that confers resistance to warfarin.

M. musculus is the house mouse, which primarily inhabits human dwellings and other structures, although it may occasionally return to the wild as feral populations.

In any event, it is sufficiently closely related that male house mice can breed with female Algerian to produce viable offspring, although this has only been observed in captivity, and does not appear to occur in the wild, perhaps because the two species inhabit different habitats.

[2] Along with evidence based on modern genetic diversity, this suggests that the species first arose in Africa, and only later migrated north to Europe, perhaps with the expansion of agricultural land into the continent during the Neolithic.

Algerian mouse, showing the paler underparts