Cervus nippon, commonly known as the Sika deer, is a species of deer native to East Asia. It is characterized by its spotted coat, which varies in color from reddish-brown in summer to grayish-brown in winter. Sika deer are medium-sized, with males typically larger than females, and they possess antlers that are shed annually. These deer inhabit a range of environments, including forests, grasslands, and wetlands. They are social animals, often found in small herds, and are known for their vocalizations, which include a distinctive whistle. Cervus nippon plays a significant role in its ecosystem by influencing vegetation dynamics.