Main Page | See live article | Alphabetical index The gizzard is a very muscular stomach that is found in birds, earthworms, and other animals. "A bird swallows small bits of gravel that act as "teeth" in the gizzard, mechanically breaking down hard food such as seeds and thus helping digestion." (Solomon et. al, 2002) Sources Solomon, E.P., Berg L.P., and Martin D.W., 2002. Biology Sixth Addition. Thomson Learning Inc., Australia, Canada, Mexico, Singapore, Spain, United Kingdom, United States pp. 664 This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.