Previously found from northern Vietnam in the south to the Russian Far East in the north,[1] it was hunted to the brink of extinction in the 19th century.

[9] They are medium-sized herbivores, though they show notable size variation across their several subspecies and considerable sexual dimorphism, with males invariably much larger than females.

Sika stags have stout, upright antlers with an extra buttress up from the brow tine and a very thick wall.

[16] The sika deer is a highly vocal species, with over 10 individual sounds, ranging from soft whistles to loud screams.

Sika males are territorial and keep harems of females during their rut, which peaks from early September through November,[17] but may last well into the winter.

Territories are marked by a series of shallow pits or "scrapes", which is digging holes (up to 1.6 m in wide and 0.3 m in deep) with forefeet or antlers,[16] into which the males urinate and from which emanates a strong, musky odor.

Hinds (does) give birth to a single fawn, weighing 4.5 to 7 kg (10 to 15 lb), which is nursed for up to ten months.

Sika deer are found throughout the city of Nara and its many parks and temples like Tōdai-ji, as they are considered to be the messengers of the Shinto gods.

[18][19] Sika deer are found in the temperate and subtropical forests of eastern Asia, preferring areas with dense understory, and where snowfall does not exceed 10–20 cm (4–8 in).

Introduced populations are found in areas with similar habitats to their native ranges, including Western and Central Europe, Eastern United States, and New Zealand.

Sika deer inhabit temperate and subtropical woodlands, often in areas suitable for farming and other human exploitation.

The status of Manchurian sika deer in China is unclear, though it is also believed to be extinct, and the sightings there are actually feral populations.

The Formosan sika deer (C. n. taioanus) has been extinct in the wild for almost two decades before individuals from zoos were introduced to Kenting National Park; the population now numbers 200.

Russia has a relatively large and stable population of 8,500–9,000 individuals of the Manchurian subspecies,[1] but this is limited to a small area in Primorsky Krai.

But in June 2020, an unmanned camera located a doe and fawn which might hold proof for Korea's last native sika deer, although the claim is contested.

[22] Sika deer have been introduced into a number of other countries, including Estonia, Latvia, Lithuania, Austria, Belgium, Denmark, France, Germany, Ireland, Netherlands, Norway, Switzerland, Russia, Romania, New Zealand, Australia, the Philippines (Jolo Island), Poland, Sweden, Finland, Canada, the United Kingdom, and the United States (in Delaware, Maryland,[23] Oklahoma, Nebraska,[23] Pennsylvania, Wisconsin, Virginia, Indiana, Michigan,[23] Minnesota, Maine, New York,[24] Texas,[23] and Wyoming).

[28] In research which rated the negative impact of introduced mammals in Europe, the sika deer was found to be among the most damaging to the environment and economy, along with the brown rat and muskrat.

[29] In the 1900s, King Edward VII presented a pair of sika deer to John, the second Baron Montagu of Beaulieu.

In Britain, Ireland, and mainland Europe, sika display very different survival strategies and escape tactics from the indigenous deer.

They have a marked tendency to use concealment in circumstances when red deer, for example, would flee, and have been seen to squat and lie belly-flat when danger threatens.

In the British Isles, sika are widely regarded as a serious threat to new and established woodlands, and public and private forestry bodies adopt policies of rigorous year-round culling.