Sunset on Nickajack Lake offers a chance to see thousands of endangered gray bats emerge from a nearby cave to start their nightly feeding. Outdoor Chattanooga will host family canoe trips to Nickajack Cave from 7 to 9:30 p.m. Fridays through Aug. 15 to witness this summertime ritual. Participants will canoe to the mouth of the cave at dusk, then paddle back to the launch after dark. Canoes, paddles and life jackets are provided on this guided trip, which is appropriate for adults and children 5 and older. Cost is $10 per person. Each trip is limited to 14 participants. Reservations are required; call 423-643-6888 or email firstname.lastname@example.org.