Gizzard

A gizzard is a muscular digestive organ found in many animals, especially birds, where it helps grind food before it passes into the intestine.

A gizzard is a muscular digestive organ found in many animals, especially birds, where it helps grind food before it passes into the intestine. Also called the ventriculus, gastric mill, or gigerium, it may contain grit or stones to assist mechanical digestion. In Canada, gizzards are relevant through poultry and wild bird biology, as well as food traditions.

Structure and function

The gizzard is a thick-walled muscular organ that performs mechanical digestion by crushing or grinding food. In birds, it is located between the crop/proventriculus and the intestine, and often contains grit or stones to aid in grinding. The organ's strong muscles and tough lining are adapted to handle abrasive material.

Occurrence in animals

Although most familiar in birds, gizzards or gizzard-like organs occur in several other animal groups. These include earthworms, some fish, some gastropods, some crustaceans, and certain insects and Molluscs. In insects and some molluscs, the gizzard may have chitinous plates or teeth.

Bird digestion

In Bird species, the gizzard compensates for the lack of chewing teeth by grinding food mechanically. It may contain gastroliths or grit, and its strong muscles and tough lining are adapted to wear from abrasive material. All birds have a two-part stomach that includes a muscular gizzard, though its size and importance vary with diet.

Terminology

The organ is also known as the ventriculus, gastric mill, or gigerium. In broader or informal use, the word gizzards can also refer to entrails or innards.