Jumping mice (subfamily Zapodinae) are a group of mouse-like rodents in North America and China.Although mouse-like in general appearance, these rodents are distinguished by their elongated hind limbs, and, typically, by the presence of four pairs of cheek-teeth in each jaw. There are five toes to all the feet, but the first in the fore-feet is rudimentary, and furnished with a flat nail. The tail makes up for 60% of its body length and is used to gain balance while bounding.