The Red Deer is our largest and only native species. It is believed to have lived on this island since the end of the last Ice Age (c. 10,000 BC). At this time they roamed freely through out Ireland, but as a result of deforestation, over hunting and the Great Famine (1845 - 1847) many populations became extinct. Thanks to the strict protection laws introduced by the estates of the Brownes; Earl of Kenmare and the Herberts of Muckross during the 19th Century, the Red Deer survived extinction by grazing the woodlands and mountains around their land in Killarney. At the turn of the 20th Century, there were in excess of 1500 Red deer in Killarney. Within the next 60 years this number fell to as few as 60. Luckely strict protection laws were then introduced and their numbers began to creep back withion the National Park. A survey undertaken in the early 90's estimated their numbers had reached 690.
The main deer range can be found on Torc, Cores and Mangerton Mountains with other herds in the lowland areas of the park. These are the only native wild Red deer that exist in Ireland today. Sika deer are potentially a threat to the genetic integrity of the Red deer herd, as they are known to be capable of interbreeding. So far no cases of crossbreeding between Red and Sika have been recorded in Killarney (as has happened in Wicklow), but the situation is being carefully monitored, and a high priority is attached to maintaining the genetic purity of the native herd. Other herds can be found in the Glendalough Valley and Turlough Hill in Co. Wicklow, also wild herds exist in Glenveagh, Co. Donegal. These are not native herds but were introduced from Scotland in the 19th Century. ?Red deer stags are easiest to see in late September and early October during the rut.