“Mice are obsolete,” the computer store man said. “Computers have built-in track pads now.” Leaving the shops behind we strolled through York’s Museum Gardens. Among the familiar squirrels scampering about this gracious arboretum, a quick flash of champagne-coloured fur revealed a different member of the rodent family.The mouse had dashed out from a crevice in a rock underneath an old hornbeam. We waited. It dashed out again. And again. It was mus musculus, more commonly known as a house mouse. Pursuing a circuit, it was probably caching food. Then, all at once, it saw us. An agonised last look at its dark storehouse, and it darted away across the foodless danger of some bare soil to another sanctuary.Who can understand the life of a mouse? What’s it li