In 1968, John Calhoun created the perfect home for eight mice. The colony grew to more than 2,200 before it slowly vanished

• In a laboratory in Maryland during the late 1960s, a small group of mice entered what looked, at least on paper, like an ideal home.
• There was no shortage of food, clean water arrived without fail, temperatures barely changed and disease had largely been removed from the picture.
• Every practical need had been anticipated.