The Bat Emergence
Watching a colony of Mexican free-tailed bats emerge is truly a special experience! During emergence, the bats spiral upwards in a counter-clockwise direction in order to gain altitude. Aerial predators, such as Red-tailed hawks, are sometimes seen catching bats as they emerge, and terrestrial predators, such as Raccoons, feed on fallen bats. The large, serpentine column of bats can travel 60 miles, one-way, and as high as 10,000 feet each night to feed on agricultural pests such as the corn earworm (a.k.a. cotton bollworm), cutworm, and webworm moths. Each bat can eat its weight in insects nightly, and the Old Tunnel colony may devour over 25 tons of moths per night! When visiting Old Tunnel, we recommend bringing a pair of binoculars to get the best view of the bat emergence. Call (866) 978-2287 to get the latest emergence time information.
Viewing the Bat Emergence
Visitors can enjoy the bat emergence from May through October by choosing three options: viewing the emergence from the Upper Viewing Area, participating in a Lower Viewing Area Tour, or making Special Group Tour reservations for your adult or youth group.
Upper Viewing Area
The upper viewing area, located adjacent to the parking area, is open nightly for use by the general public. The scenic view from the upper viewing area allows visitors to experience the rugged beauty of the Texas Hill Country, and many bicyclists, motorcyclists, and car clubs stop at Old Tunnel to enjoy this view. Bats are best viewed from this area during August and September when bat emergence times are earlier and more light is present. Fantastic views of Red-tailed hawks feeding on emerging bats can also be seen from this area. No fees are charged and no passports or permits are required.
Lower Viewing Area Tour - A close-up view of the emergence is one of the most unique experiences in nature. The flapping of millions of tiny wings is usually audible and often creates a light wind that can be felt by visitors in the lower viewing area. Many visitors also enjoy listening to the soft clicking sounds the bats use to communicate with each other. Lower viewing area tours are conducted Thursday through Sunday, May through October. An educational program is given about bats, with an emphasis on the fascinating life history of the Brazilian free-tailed bat (T.b. mexicana).
Seating and Admission
Seats are filled on a first-come, first-served basis with a maximum seating capacity of 70 visitors. Reservations not accepted. The activity tour fee for the lower viewing area is $5.00 per person regardless of age. We do not accept the State Parks Pass or the Bluebonnet Pass. These Passes cover the entrance fee to State Parks. Activity and tour fees are not covered by these passes. We also do not accept Limited Public Use and Annual Public Hunting Permits. We only accept cash or check. This park does not have cash on hand and is not able to make change; please bring the exact amount of cash for payment.
Visitors are advised to arrive 30 minutes to one hour prior to the start of the lower viewing area tour. During the high-use times, such as holidays and Friday and Saturday nights, visitors are encouraged to arrive one hour or more prior to the start of the lower viewing area tour. Tours begin approximately one hour prior to bat emergence time. Composting toilets are present at the upper viewing area, but are only open during the evening hours from May through October and during special events.
Special Group Tours
Conducted at the lower viewing area Monday through Wednesday evenings from May through October for organized groups of up to 70 people. Reservations are required. Passports or permits, including the Texas State Parks Pass, are not accepted. Special Group Tour fees are as follows: Youth Groups: $1 per person, 35 person minimum, 70 person maximum; Non-Youth Groups: $2 per person, 35 person minimum. 70 person maximum. To schedule a Special Group Tour, please e-mail the park.