The most conspicuous wildlife species to return to the blast zone have been Roosevelt elk (Cervus elaphus) and Columbia black-tailed deer (Odocoileus hemionus). Large mammals did not survive the blast but animals from adjacent, less-disturbed areas were able to move into the blast zone soon after the eruption. The animals found prime habitat due to the availability of high quality summer forage from surviving plants and winter forage from grass and clover planted to for erosion control. The availability of winter forage contributed greatly to elk recovery in the blast zone.
It is not unusual to see large herds of bull elk running together on the debris avalanche or in the blast zone north of the volcano. Elk viewing is a very popular activity among Monument visitors.