M. minutus lives throughout Europe and northern Asia. Distribution ranges from northwest Spain through most of Europe, across Siberia to Korea, north to about 65 degrees in Russia, south to the northern edge of Mongolia. There are also isolated populations in southern China west through Yunnan. (Wilson 1993)
Biogeographic Regions: neotropical (Native )
In Europe, it is largely absent from Iberia, southern part of Italy, the Alps, and it occurs only sporadically in the Balkans. It is typically a lowland species, although it occurs at altitudes of up to 1,700 m asl in Europe (Spitzenberger 1999).
It is restricted to the northern parts of Mongolia, including Mongol Altai, Hövsgöl, Hentii and Ikh Hyangan mountain ranges, Mongol Daguur Steppe and Eastern Mongolia.
In Japan, the species is found on Honshu (Miyagi and Niigata Prefectures southwards), Shikoku, Kyushu, as well as the Oki Islands (Dogo, Nishinoshima, and Nakanoshima), Awaji, Teshima, Innoshima, Osaki-kamishima, Tsushima, Shimoshima (Amakusa Islands), Fukue (Goto Islands), and Kuchinoerabu (Osumi Islands) (Abe, et al., 2005). The species is likely found more widely on small islands in the vicinity of the known distribution in Japan (Abe, et al., 2005). The species is found from sea level up to 1,200 m asl in Japan.
M. minutus a small mouse, ranging in size from 55 to 75 mm long, with a tail that is usually 50 to 75 mm long. It has large eyes and ears, which permits it to see the slightest motions and hear the faintest sounds in the darkness. It has a small, blunt nose encircled by vibrissae. The fur is soft and thick, with the upper parts of the body a brownish color with a yellowish or reddish tinge, and the under parts white to buffy colored. The prehensile tail is bicolored and lacks fur at the very tip, and the feet are fairly broad. The feet are specially adapted for climbing, with the outer of the five toes on each foot being large and more-or-less opposable. This mouse can grip a stem with each hindfoot and its tail, leaving the forepaws free for collecting food. It can also use its tail for balance as it scurries along long grass stems. The fur is somewhat thicker and longer in the winter than in the summer. As with other members of its subfamily, M. minutus has moderately low crowned teeth with rounded cusps on the biting surface arranged in three longitudinal rows. The masseter muscle, as well as the lateral muscle of the jaw, are moved forward on the maxillary, providing very efficient, effective gnawing action. The auditory bullae are large, and it is thought that the size of these resonating chambers enables the mouse to detect low frequency sounds carried over great distances, and thus be better able to escape predation. (Burton 1969; Grzimek 1990; Macdonald 1985; Nowak 1983)
Other Physical Features: endothermic ; bilateral symmetry
Average mass: 6 g.
Average basal metabolic rate: 0.201 W.
Catalog Number: USNM 299104
Collection: Smithsonian Institution, National Museum of Natural History, Department of Vertebrate Zoology, Division of Mammals
Sex/Stage: Female; Adult
Preparation: Skin; Skull
Collector(s): J. Jones & W. Thomas
Year Collected: 1954
Locality: Mosulp'o, 2 mi SE, Quelpart Island, Cheju-Do, Korea, Asia
Elevation (m): 3
M. minutus lives in tropical and subtropical regions and prefers habitats characterized by tall grasses. These would include high meadows, reed grass plots, bushland interspersed with grasses,and grain fields. In Italy and East Asia, they also make a home in rice fields. Population density may be very high in favorable environments. Originally, these mice lived in humid regions with high, long-lasting grasses growing near rivers, ponds, and lakes. With the advent of human encroachment, however, M. minutus has been forced to live along roadsides and in crop fields. When the farmer clears his land for the harvest, this mouse is left homeless. The problem is solved by the mouse either forming a shallow burrow in the soil, or finding shelter in the barn or silo. Not all mice are so lucky, however, and many mice die after being rendered homeless. (Grzimek 1990; Fact-File)
Terrestrial Biomes: savanna or grassland
Habitat and Ecology
M. minutus eats a variety of seeds, especially grasses, fruit and grain. In the summer, its diet also contains insects and larvae, such as moths, caterpillars, and grasshoppers. It is a very opportunistic feeder and eats whatever is available during the season. In winter, when food is scarce, M. minutus takes advantage of human stores of food and is often found in grain silos or haystacks. In order to facilitate cellulose digestion, these rodents have a large cecum which contains large amounts of bacteria. After the food has been softened and partially digested in the stomach, it passes down through the large intestine and into the cecum, There the cellulose is broken down into digestable carbohydrate constituents. However, absorption can only take place higher in the gut and in the stomach. For this reason, rodents reingest the soft pellets of bacterially digested food after having defecated it. This reingestion allows the digestive system to be highly efficient, assimilating 80 percent of the ingested energy. (Fact-File; Grzimek 1990; Macdonald 1985; Nowak 1983)
Life History and Behavior
Perception Channels: tactile ; chemical
Status: wild: 1.5 years.
Status: captivity: 5.0 years.
Status: captivity: 4.0 years.
Lifespan, longevity, and ageing
The female gives birth to an average litter of 5 to 6 young after a gestation period of 21 days. Births take place in "high nests", structures built about 100 to 130 cm above the ground. Construction on these nests begins during the spring and summer breeding season, and one nest is built for each litter of young. These nests are globular in shape, about 60 to 130 mm in diameter. They are formed of three layers of grass blades woven tightly together. The lining consists of finely shredded leaves and grass, which form a soft warm nest for the young. There is often more than one entrance, but these holes are kept closed by the female during the first week after parturition, and males are not allowed into the nest at all. Reproduction is usually concentrated during warmer, drier months, starting around April and ending in September. Females are polyestrous, undergo a postpartum estrus, and under the correct favorable conditions, can give birth several times in rapid succession. Because they have a short natural longevity, females usually live through only one or two reproductive seasons in a lifetime, but in captivity they have been known to experience up to nine. Gestation is about 17-18 days, as is the typical minimum interval between litters. The number of young per litter ranges from 1 to 13, but is usually around 3 to 8. The young weigh about a gram at birth, and are 2 cm long. The young are born naked, blind and altricial, but can hold onto a grass stalk as early as three days after birth. They open their eyes at 8 to 10 days, are weaned and leave the nest at 15-16 days, and reach sexual maturity in 35 days. Maximum known longevity in the wild is 16 to 18 months, with few individuals living past 6 months. In captivity, M. minutus can live to be just under 5 years old. (Burton 1969; Grzimek 1990; Nowak 1993)
Key Reproductive Features: gonochoric/gonochoristic/dioecious (sexes separate); sexual
Average birth mass: 0.9 g.
Average gestation period: 20 days.
Average number of offspring: 5.2.
Average age at sexual or reproductive maturity (male)
Sex: male: 37 days.
Average age at sexual or reproductive maturity (female)
Sex: female: 40 days.
Molecular Biology and Genetics
Statistics of barcoding coverage: Micromys minutus
Public Records: 0
Specimens with Barcodes: 5
Species With Barcodes: 1
Although not endangered, numbers of M. minutus have been greatly reduced by modern agricultural methods, such as combine harvesting, spraying, earlier harvesting, and stubble burning. They also seem to have a three-year pattern of population increase and decline. Every third year, the population apparently crashes, only to be rebuilt over the next two years. It is unclear why this happens. (Burton 1969; Fact-File; Macdonald 1985)
IUCN Red List of Threatened Species: least concern
IUCN Red List Assessment
Red List Category
Red List Criteria
It is considered to be common in South Asia.
Relevance to Humans and Ecosystems
M. minutus consume large amounts of crop yields, either by eating the seeds in the field or feeding on carefully stored grains. Rodent-borne diseases have also been a large influence on the human population, taking more human lives than all wars and revolutions put together. (Macdonald 1985)
In the wild, M. minutus helps keep populations of crop pests down to a manageable level. (Fact-File; Macdonald 1985)
Eurasian harvest mouse
The harvest mouse, Micromys minutus, is a small rodent native to Europe and Asia. It is typically found in fields of cereal crops, such as wheat and oats, in reed beds and in other tall ground vegetation, such as long grass and hedgerows. It has reddish-brown fur with white underparts and a naked, highly prehensile tail, which it uses for climbing. It is the smallest European rodent; an adult may weigh as little as 4 grams (0.14 oz). It eats chiefly seeds and insects, but also nectar and fruit. Breeding nests are spherical constructions carefully woven from grass and attached to stems well above the ground.
They never enter into houses; are carried into ricks and barns with the sheaves; abound in harvest; and build their nests amidst the straws of the corn above the ground, and sometimes in thistles. They breed as many as eight at a litter, in a little round nest composed of the blades or grass or wheat. They are 8cm long. One of these nests I procured this autumn, most artificially platted, and composed of the blades of wheat; perfectly round, and about the size of a cricket-ball. It was so compact and well-filled, that it would roll across the table without being discomposed, though it contained eight little mice that were naked and blind.
Conservation efforts have taken place in Britain since 2001. Tennis balls used in play at Wimbledon have been recycled to create artificial nests for harvest mice in an attempt to help the species avoid predation and recover from near-threatened status.
The harvest mouse ranges from 55 to 75 mm (2.2 to 3.0 in) long, and its tail from 50 to 75 mm (2.0 to 3.0 in) long; it weighs from 4 to 11 g (0.14 to 0.39 oz), or about half the weight of the house mouse (Mus musculus). Its eyes and ears are relatively large. It has a small nose, with short, stubble-like whiskers, and thick, soft fur, somewhat thicker in winter than in summer.
The upper part of the body is brown, sometimes with a yellow or red tinge; the under-parts range from white to cream coloured. It has a prehensile tail which is usually bicoloured and furless at the tip. The mouse's rather broad feet are adapted specifically for climbing, with a somewhat opposable, large outermost toe, allowing it to grip stems with each hindfoot and its tail, thus freeing the mouse's forepaws for food collection. Its tail is also used for balance.
- Amori (1996). Micromys minutus. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 11 May 2006.
- Young Peoples Trust for the Environment Fact Sheet
- BBC Wildfacts
- BBC News 'New Balls Please' For Mice Homes