Adventures and Expedition Philippines Inc., and North Adventurer. Daily circadian flight of bats from the Bat Cave occur at dusk. References External links Photo of the Callao Cave's 1st Chamber from Panoramio Photo of the Callao Cave's 3rd Chamber from Panoramio Photo of the Callao Cave's 4th Chamber from Panoramio Photo of the Callao Cave's 5th Chamber from Panoramio 2019 article on Homo luzonensis in Nature Caves of the Philippines Sierra Madre (Philippines) Landforms of Cagayan Paleoanthropological sites Paleontology in the Philippines Tourist attractions in Cagayan