Asia

The Indochinese Sika Deer is one of many sika subspecies. It is smaller than the rest, which is an adaptation to its former tropical habitat. The Indochinese Sika is extinct in the wild due to the felling of the forests where they once lived. The density of human beings has spread into this area, making it now one of the most densely populated areas in the world. Some sika species have been released into the wild in Denmark, as in parks like Jægersborg Dyrehave and Marselisborg.

Sika deer can be active throughout the day, though in areas with heavy human disturbance they tend to be nocturnal. They are solitary or live in small groups, apart from the rutting season when large herds gather in autumn and winter. Females gestate for 30 weeks up until May/June when the calves are born. Usually one calf is born, rarely two. Each calf weighs about 4 kg. A calf suckles from its mother for 8–10 months.

Sika males are territorial and keep harems of females during the rutting season. Territories are marked off with a series of shallow pits or scrapes in the earth into which they urinate. This sends a strong musky odour to other males to indicate that the area is occupied. Fights between males are sometimes fierce and long and may even end with one dying of its injuries. 

Sika deer can make many different sounds. Ten individual sounds have been recorded, ranging from soft whistles to loud screams.

Note that only the stags have antlers. The antlers are shed every winter and grow out with velvet (fur-like skin) in the spring. The antlers grow larger each year until the stag is old. The stag scrapes off the skin and is ready for autumn when the rutting season and the fight for females begin.