Sika Deer are smaller than, but very closely related to red deer. The Sika is native to Asia, but introduced populations can be hunted in a number of locations Globally. The main populations in Europe that are viable for hunting reside in the UK and Czech Republic. Sika deer were introduced to Czech republic in the late 19th early 20th Century. the spread has been significant and it is estimated there are 6000 individuals in the Czech Republic, and that population is rising. As a non native species it is interbreeding with Red deer, and similarily to the UK control is required. 

The origins of Sika in Cz Republic are still somewhat unknown and the limited genetic studies that have been conducted confirmed that the founder individuals of the Czech population originated from both native island (Japanese Islands) and native mainland (Far East Russia) populations.