This article is about the digestive croup. For the top of the hindquarters, also known as the croup, see
Rump (animal).
The crop (also the croup, the craw, the ingluvies, and the sublingual pouch) is a thin-walled, expanded portion of the
alimentary tract, which is used for the storage of food before
digestion. The crop is an anatomical structure in vertebrate animals, such as
birds, and invertebrate animals, such as
gastropods (snails and slugs),
earthworms,[1]leeches,[2] and
insects.[3]
Insects
Cropping is used by
bees to temporarily store nectar of flowers. When bees "suck" nectar, it is stored in their crops.[4]
Other
Hymenoptera also use crops to store liquid food. The crop in eusocial insects, such as
ants, has specialized to be distensible, and this specialization enables important communication between colonial insects through
trophallaxis.[5]
The crop can be found in the
foregut of insects.[6]
Birds
In a
bird's digestive system, the crop is an expanded, muscular pouch near the
gullet or throat. It is a part of the digestive tract, essentially an enlarged part of the
esophagus. As with most other organisms that have a crop, it is used to temporarily store food. Not all bird species have one. In adult doves and pigeons, it can produce
crop milk to feed newly hatched birds.[7]
Scavenging birds, such as
vultures, will gorge themselves when prey is abundant, causing their crop to bulge. They subsequently sit, sleepy or half torpid, to digest their food.
"Craw" is an obsolete term for "crop",[13] and this is still seen in the saying "it sticks in my craw" meaning "I can't [metaphorically] swallow it", that is, that a situation or other entity is unacceptable, or at any rate annoying.[14]
^Triplehorn, Charles A; Johnson, Norman F (2005). Borror and DeLong's introduction to the study of insects (7th ed.). Australia: Thomson, Brooks/Cole.
ISBN9780030968358.