Working for a natural history museum, we get to explore places that are probably interesting only to researchers and scientists. In the past, our forebears trekked mountains, scanned forests and dove into the depths of seas. Now, we have gone into the vast underworld of Philippine caves. With headlights to give us vision, we now enter places of complete darkness enveloped by deafening silence.
For many, caves might be the scariest of all places, a world of the unknown oftentimes associated with the works of darkness and evil. And for some, caves are places for tourism and recreation. But for us, they are living laboratories, places of learning and discovery, the main reason why we explore them in search of bats, birds, frogs, snakes, insects and even microbes.
The municipality of Mabini in Pangasinan is haven to a number of caves both of ecotourism and scientific value. Fully geared, a team of biologists and researchers from the Museum of Natural History and students of the BIO 154 Cave Ecology course visited a portion of the Cacupangan Cave, a 4-kilometer stretch of limestone and underground river beneath the lands of at least four barangays.
We had to leave Los Baños on Friday night (9 April 2015) for the 7-hour travel to Mabini, Pangasinan. It was tiring but everyone in the team were all excited to experience what would await us. Early morning the following day, we were welcomed by friends from Balincaguin Conservancy and the local government of Mabini headed by Mayor Carlitos Reyes.
On board an old truck, we travelled along the bumpy and winding road to the main mouth of Cacupangan Cave System. The name of the cave was derived from the “kupang” trees (Parkia timoriana) widespread all over the area and line the road leading to the cave. The place is neat, perfect for camping, since the frontage of the cave has been developed by landowners into a quaint resort.
There are small pavilions for picnics and charcoal stoves for visitors who wish to grill their food. Clear and ice-cold water flows through a pipe from the cave. The communities near the area actually get water from the cave for household use.
It was a long, sleepless travel but the camp must be set. Everyone looked for their own spot perfect to pitch their tents and hammocks. While some collected dry leaves to put under their tents to serve as cushion, others preferred to rig their quarters on cemented pavements. A group of students even forgot to bring the poles for their tents.
“Even the young is forgetful,” the older ones commented with glee.
Right after setting up camp, the team were organized into groups. Each student was tasked to conduct a simple exploratory project as part of the course requirements. Before entering the cave, we were given house rules for the three-day camp as well as policies to be followed when exploring the cave. Our guides in Balincaguin reiterated the golden rule for cavers, “No helmet and headlight, no entry.”
Twenty students did their individual short-term projects. A team collected bats inside and outside the cave while another mapped the cave and the specific location of bat roosts. One student swabbed the bats hoping to isolate microorganisms from them. The cave has also become a “crime scene” - bat carcasses have been laid on the cave floor and surrounded by crime scene tapes; students will monitor what insects and other arthropods will feed on the dead bats. Even the air inside the cave, suspected to carry both good and bad microorganisms was checked.
The other group was more amused of the plants around the cave though the vegetation is not like the lush evergreen forest that you find in mountains. Guava, cainito and figs were abundant, perfect for bats and birds which really love the delicious fruits. Small herbaceous plants such as begonias and aroids live well on the moist and cool walls of the cave entrance where cold water freely and continually flows from. Noxious weeds like hagonoy (Chromolaena odorata) also flourish in the place. But trees do not grow as big as those we find in forests because of the pressure from kaingin and harvesting by locals for charcoal production.
As we entered the cave, the cold water dampened our clothes and filled our boots making it difficult to walk. On the walls and within the piles of rocks are creepy crawlies like whip spiders and vinegaroons. Hiding in crevices in the muddy floor are brown to bright orange Hirtipes crabs waiting for their prey. Looking into the water, you will find the slimy eels trying to escape for fear of being stepped upon. After all, they are pulutan perfect with a bottle of ice-cold beer.
As we reached the place people called the “Logged Room,” the deafening silence was replaced by ‘clicking’ sounds and wingbeats of the unseen creatures crazily flying above us. The scent of flowing water suddenly became stinky because of the mounds of bat guano. Using our mist nets, we caught four species of bats inside the cave. From these bats, a student collected ectoparasites which feed on the bat’s blood.
Some students looked for their “frog prince” - the male frogs that attract females using their golden “voice.” They stayed out late at night to record frog calls, identifying differences between and among species inside and outside the cave. We even had a team to collect reptile specimens, unfortunately, they did not find any. Caving is never complete without appreciating the unique and astonishing rock formations patiently formed by water dripping through the ceiling and walls for hundreds of years. There were stalagmites on the ground, stalactites from the ceiling; and at some places, they sometimes meet and form a column. For some people, they are merely solid rocks but for cave biologists like us, a growing formation is as alive as a child that matures through the years.
A cave is also a perfect place to feed a photographer’s hunger for bewildering subjects. Friends from Balincaguin are also cave photographers who taught us the basic skills for lighting and capturing images in a place of total darkness. There were white formations and perfectly engineered ceilings of stalactites. Mabini’s caves are still biologically unexplored.
While most fear to venture inside caves, the Museum considers them as a wellspring of new knowledge. Caves are our portals to unravelling the beauty of nature hidden in the dark.