These tasks can include grooming and feeding. Harvest mice have a prehensile tail that functions as an extra limb during climbing . During the lactation period, the pups are able to climb a vertical bar by the time they first emerge from their nest. At 3-7 days they learn hand grasping, and at 6-9 days they learn food grasping. Between 6-11 days, they adopt a quadrupedal stance, and at 10-11 there is tail prehension, and righting at 10-12 days. The righting response in harvest mice develops earlier, but takes longer to master than the other skills the pups learn. They cannot climb horizontally by the time they are weaned, suggesting that horizontal climbing is not as essential as vertical climbing. Their predators include domesticated cats, barn owls, tawny owls, long-eared owls, little owls, and kestrels. In most rodent species, females prefer familiar males to unfamiliar ones. The adaptive preference of mating with familiar males is not uncommon as familiarity is a proxy for quality that is seen in many solitary animals.. Harvest mice are thought to be solitary, and the preference for familiar males over unfamiliar is a mechanism for inbreeding avoidance. There is no size dimorphism between the sexes so the females are considered dominant over the males. Females do not show interest in the male's odor. When females are in oestrus they spend more time with familiar males, and prefer the one that is heavier. While in dioestrus, the female spends more time with unfamiliar males. In most years in Britain, harvest mice build their first breeding nests in June or July; occasional nests are built earlier in April or early May. They prefer building their breeding nests above ground. In Russia, harvest mouse breeding occurs in November and December in cereal ricks, buckwheat, and other cereal heads. Due to their habitat, harvest mice are threatened by a number of anthropogenic effects such as farming, pesticide use, crop rotation, habitat destruction, fragmentation, and wetland draining. Grasslands in Japan are rapidly decreasing in area, and are also becoming increasingly fragmented . Urbanisation rate is another parameter for habitat destruction; in areas that are being urbanised more quickly, other species in the area will be forced into smaller areas. Spatial relationships between habitat patches are becoming increasingly important in these areas. Small salamanders require stagnant water in unsuitable habitats in more urban areas and since harvest mice have a similar ability to disperse, there is a risk that they may be forced to adapt to such environments when their preferred habitat is absent in the future.