What is "cheek pouch"

Cheek \Cheek\ (ch[=e]k), n. [OE. cheke, cheoke, AS. ce[`a]ce, ce[`o]ce; cf. Goth. kukjan to kiss, D. kaak cheek; perh. akin to E. chew, jaw.]

1. The side of the face below the eye.

2. The cheek bone. [Obs.]
   --Caucer.

3. pl. (Mech.) Those pieces of a machine, or of any timber, or stone work, which form corresponding sides, or which are similar and in pair; as, the cheeks (jaws) of a vise; the cheeks of a gun carriage, etc.

4. pl. The branches of a bridle bit.
   --Knight.

5. (Founding) A section of a flask, so made that it can be moved laterally, to permit the removal of the pattern from the mold; the middle part of a flask.

6. Cool confidence; assurance; impudence. [Slang]

   Cheek of beef. See Illust. of Beef.

   Cheek bone (Anat.) the bone of the side of the face; esp., the malar bone.

   Cheek by jowl, side by side; very intimate.

   Cheek pouch (Zo["o]l.), a sacklike dilation of the cheeks of certain monkeys and rodents, used for holding food.

   Cheeks of a block, the two sides of the shell of a tackle block.

   Cheeks of a mast, the projection on each side of a mast, upon which the trestletrees rest.

   Cheek tooth (Anat.), a hinder or molar tooth.

   Butment cheek. See under Butment.

n. (context anatomy zoology English) A pouch in the cheek of some animals, usually used to carry food.

n. a membranous pouch inside the mouth of many rodents (as a gopher)

Cheek pouches are pockets on both sides of the head of some mammals between the jaw and the cheek. They can be found on mammals including the platypus, some rodents, and most monkeys, as well as the marsupial koala. The cheek pouches of chipmunks can reach the size of their body when full.