General: Long-tailed Pocket Mice (Chaetodipus formosus) are
small, buffy-gray mice with small ears; a long, tufted tail; and no other marks. The head and body are about 3-inches long, and the tail is 4-5 inches long. They have external, fur-lined cheek pouches; run on all four feet; and have a crest of long hairs on the top of the tail.
Like kangaroo rats, pocket mice have external, fur-lined cheek pouches that they use
to carry seeds and other food items to and from their burrows and seed caches. Most
animals carry food in their mouth (e.g., dogs and cats) or inside the
cheeks (chipmunks), but pocket mice actually have an extra pouch on
the outside of their cheeks, similar to the pouch of an Australian kangaroo.