Birch mice | Sminthidae

Berkenmuizen | Ratones listados

Small mouse-like rodents with a tail one and a half to two times the length of the body, wrapped round grass stems in climbing — half prehensile, and more a fifth limb than a balancing rod. In most species a narrow dark line runs down the back, sometimes with paler stripes beside it; the coat is otherwise an unremarkable yellowish brown. The feet are small and the toes long, fit for working up through the herb layer to seeds, berries and insects, on which the animals pass the summer. Hibernation is extraordinarily long for their size: in the north a birch mouse spends more than eight months in a chamber it has dug underground, and on cool summer nights it falls into torpor as well. There is one litter a year, and few young in it — slow breeding for so small a rodent.