Pocket mice
| Pocket mice Temporal range: Early Miocene–Recent |
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| Silky pocket mouse (Perognathus flavus) | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | Heteromyidae |
| Subfamily: |
Perognathinae Coues, 1875 |
| Genera | |
Perognathinae is a subfamily of rodents consisting of two genera of pocket mice. Most perognathines live in complex burrows within the deserts and grasslands of western North America, They feed mostly on seeds and other plant parts, which they carry in their fur-lined cheek pouches to their burrows.
There are about twenty-six members of the subfamily Perognathinae divided among two genera. They are all small rodents. Adaptations include partially fused vertebrae in the neck, short fore limbs and much enlarged bullae (bubble-shaped bones in the skull). The dental formula is 1/1, 0/0, 1/1, 3/3 making twenty teeth in total. The molars have two-lobed cusps. The upper incisors are grooved and the enamel on the molars is quickly worn away by chewing leaving the dentine exposed. The check teeth have roots.
Fur-lined cheek pouches are a feature across the family Heteromyidae. They have openings near the mouth and extend backwards along the sides of the neck. The fur on the animal's body is in general short and fine and often matches in colour the soil of the region in which the animal lives, being some shade of buff, pale brown, reddish-brown or grey.
Perognathines are distributed from southwestern Canada through the western and Great Plains regions of the United States to central Mexico. They are creatures of open country, mostly specialising in prairies, arid lands and desert fringes.
Pocket mice are adapted for life in deserts and other arid environments where they largely feed on dry seeds. They carry most of the seeds they find back to their burrows in exterior cheek folds lined with fur rather than in cheek pouches inside the mouth as do hamsters. This is because carrying the food in the mouth would involve wetting it and moisture needs to be conserved as much as possible in dry environments. Most species store the seeds they gather in special chambers in the burrow where they absorb moisture from the humid air.
It has been found that there is little hoarding done in the winter but that food is most commonly stored in the autumn and spring. Heteromyds use sight and olfactory clues to locate possible food and then use their fore-feet to manipulate objects. Pocket mice hunt around under vegetation or debris for individual food items. It has been found that they forage more efficiently than kangaroo rats and this is thought to be due to the fact that they handle their finds more and are better able to distinguish between food and non-food items.
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Wikipedia