Harvest Mouse (Grassland Gymnastics Mouse)

The harvest mouse (Micromys minutus) is a small rodent native to Europe and Asia. It has reddish-brown fur with white underparts and a naked, highly prehensile tail, which it uses for climbing. An adult may weigh as little as 4 grams. They have a reddish-yellow coat with a distinct white underside, small hairy ears, and a much blunter nose than other mice. They are mostly nocturnal, although are active during the day in warm summer months. Harvest mice are less active in winter but do not hibernate; they stay close to the ground for warmth and insulation and store food to sustain them through the winter months. Harvest mice can be found in a variety of habitats including rough grasslands, reed beds, riparian margins, roadside verges, hedgerows, cereal crops (e.g. oats and wheat), field margins, and wild bird seed crops. They eat a mixture of seeds, berries, and insects, although moss, roots, and fungi may also be taken. Harvest mice sometimes take grain from cereal heads, leaving characteristic sickle-shaped remains. Unlike some rodents, harvest mice don’t eat enough to cause damage to crops. So farmers don’t mind having these tiny gymnasts in their fields. The mice may even help farmers by eating insect pests. These mice are not dangerous, there are no specific diseases that are known for spreading to humans either. Like other species of rodents, are very active contributors to the ecosystem, wildlife, and nature around them. They actively participate in pollination by being pollen bearers and serving as transporters for pollen. They communicate using their senses, primarily through chemical responses and tactile behavior. One feature, other than its small size which makes the harvest mouse truly unique amongst mammals is its tail. The harvest mouse has a tail about as long as its own body which can be used to hold onto things just like a monkey does. This prehensile tail is useful to the mouse when climbing amongst the stems of corn and grass in a field enabling it to maintain its balance and spread its weight. They are excellent climbers and can move about off the ground in tall grass, reeds, or bramble during the summer and autumn. Their hearing is acute and they will react sharply; they either freeze or drop into cover in response to rustling sounds up to 7m away. Harvest mice don’t live long, probably only up to 18 months, but they do reproduce quickly. Their breeding season begins in May and sometimes lasts until December. They can raise to seven litters during that time, each consisting of up to eight young. Harvest mice are thought to be solitary, and the females prefer familiar males over unfamiliar. When females are in oestrus they spend more time with familiar males and prefer the heavier ones. Pregnant females construct specific breeding nests about 10 cm across (double the size of a non-breeding nest) and gestation takes 17 – 19 days. Females give birth to up to seven young who are dependent on their mother for the first two weeks of their life. They are born blind and without fur, weighing no more than 0.8 g each. Grey fur starts to develop after four days, teeth at one week, and their eyes open after around nine days. They venture outside the nest at around 11 days and their golden fur starts to come in at two weeks. One of the best ways of spotting the presence of harvest mice is to look for their nests. The nest of a harvest mouse is a beautiful structure of interwoven grass leaves, usually created some 50cm off the ground and about the size of a tennis ball. It is made by pulling leaves of adjacent grasses together, shredding them along their lengths, and weaving them together to form a spherical nest suspended between the grass stems. In this way, the grass which forms its nest continues to live so it will remain green and provide ideal camouflage. If its nest should turn brown then it will be abandoned. Because harvest mice are active both night and day, they can be preyed on by several different predators even though they usually only constitute a very small proportion of their diet. Predatory species include mustelids (such as weasels and stoats, and polecats), foxes, domestic cats, owls, hawks, corvids, shrikes, and pheasants. Young may be eaten by blackbirds or even toads. Globally harvest mice are not endangered and they are currently listed as Least Concern on the International Union for the Conservation of Nature (IUCN)’s Red List. However, according to the Mammal Society IUCN-authorised Red List of British Mammals, they are Near Threatened in Great Britain as a whole. In Scotland, where we know very little about their numbers, they are Critically Endangered, in Wales they are Vulnerable and in England, they are classified as Least Concern. As of 2019, the harvest mouse is protected under the 1981 Wildlife and Countryside Act of 1981 and the UK Post-2010 Biodiversity Framework: Implementation Plan. #Wildlife #PrehensileTail #Grassland