Several hundred thousand years ago, when a land bridge connected Taiwan and mainland China, the Formosan sika migrated to Taiwan. Possible reasons for this move include a more hospitable terrain and climate, and a relative scarcity of carnivores such as lions and tigers.
梅花鹿可能改寫近代史台灣梅花鹿來自亞洲大陸，在數十萬年前，台灣和大陸仍相連時移入，因地形、氣候的影響，逐漸演化成台灣特有亞種（在分類學上，同種動物若外形上有顯著差異，彼此稱為亞種）。