栗 - chestnut

Japanese chestnut (Castanea crenata)

acorn

light chestnut (horse coat color)

red chestnut (horse coat color)

deep brown color

Auckland teal (Anas aucklandica); Auckland Islands teal

black-capped squirrel monkey (Saimiri boliviensis)

Central American squirrel monkey (Saimiri oerstedii)

black chestnut (horse coat color)

chipmunk (esp. the Siberian chipmunk, Tamias sibiricus)

Taiwanese squirrel (subspecies of Pallas's squirrel, Callosciurus erythraeus thaiwanensis)

red squirrel (Sciurus vulgaris)