Omnivore /ˈɒmnivɔər/ is a consumption classification for animals that have the capability to obtain chemical energy and nutrients from materials originating from plant and animal origin. Often, omnivores also have the ability to incorporate food sources such as algae, fungi, and bacteria into their diet as well.
Omnivores come from diverse backgrounds that often independently evolved sophisticated consumption capabilities. For instance, dogs evolved from primarily carnivorous organisms (Carnivora) while pigs evolved from primarily herbivorous organisms (Artiodactyla). What this means is that physical characteristics are often not reliable indicators of whether an animal has the ability to obtain energy and nutrients from both plant and animal matter. Due to the wide range of entirely unrelated organisms independently evolving the capability to obtain energy and nutrients from both plant and animal materials, no generalizations about the anatomical features of all omnivores can realistically be made.
The variety of different animals that are classified as omnivores can be placed into further categories depending on their feeding behaviors. Frugivores include maned wolves and orangutans;insectivores include swallows and pink fairy armadillos;granivores include large ground finches and humans. (This is due to the average human diet mainly consisting of grains, with rice, maize and wheat comprising two-thirds of human food consumption).