Gunung Mulu National Park, in the Malaysian Borneo, is one of those places every naturalist knows about and dreams to visit at least once. The formula is simple: one of the largest cave systems in the world; few degrees away from the Equator; an elevation range of over 2,000 meters. The result is a fascinating mix of habitats and geomorphological formations, including massive caves and limestone pinnacles immersed in a layered and divers rainforest. It’s no surprise that the park has been designated a UNESCO World Heritage Site.

The cave ecosystems, always fascinating in their own right, reach their climax in the tropics in terms of biological diversity, and in Mulu, everything is enhanced. The enormous chambers are home to colonies of swiftlets and bats, whose guano provides sustenance for communities of bacteria, fungi and detritivorous insects. Naturally, predators are not missing: in the darkness, snakes sense the air, ready to snatch a flying prey, while the cave floor and walls represent a hunting ground for spiders and giant centipedes.

At dusk, around three million bats leave the impressive Deer Cave for the night hunt, in an uninterrupted exodus lasting over thirty minutes. During this magical moment begin the dance of the bat hawks, birds of prey specialized in procuring themselves a bat-based dinner.