Living in the grass is a tiny mouse: the tiny harvest mouse, with a wonderful scientific name that sounds like the title of a Charles Dickens Novel, Micromys minutus. It is the only British mammal with a prehensile tail. It uses its tail to hold on to the slender grass stems, at the tops of which it builds a nest.
|Photo: Nick Fewing
These tiny mammals (just around 5 cm long) build a spherical nest of tightly woven grass at the top of tall grasses, in which the female will give birth to about six young.
In the fields, we see cows and horses brushing away flies with their tails; often they will stand side-by-side and end-to-end, and help each other. Two tails are better than one! In nature, tails are put to good use. Just as a tight-rope walker uses his pole for balance, so for some species, a tail provides balance. When running, a squirrel uses its tail as a counterbalance to help the squirrel steer and turn quickly, and the tail is used aerodynamically in flight. But many animals, such as monkeys and possums, use their tail as an extra limb. Their tail is prehensile; which means it is used to grab hold of things.
Harvest mice are weavers or basket makers. Shredding grass by pulling it through their teeth, they use the strips to weave a hollow nest, about the size of a tennis ball, about 50 – 100cm above the ground and secured to grass stems. Harvest mice can breed up to three times a year, and build a new nest each time. While the adults will abandon their young once they are weaned, the pups continue to use the nest.
Harvest mice have many predators: weasels, stoats, foxes, cats, owls, hawks, crows, even pheasants, but another danger is one nature had not foreseen - the combined harvester.
While the harvest mice are not a species in danger, they are nonetheless on the conservation list as their numbers are thought to be in decline.
So remember this, when next you are walking in a field. You are walking through the home of the harvest mouse.
Ray Noble is a chartered biologist and Fellow of the Royal Society of Biology