Puerto Princesa Underground River Information Puerto Princesa’s pride is easily the Puerto Princesa Subterranean River (or Underground River), a UNESCO World Heritage Site and one of the New 7 Wonders of Nature.
The 8.2-kilometer river, said to be the longest navigable underground river in the world, winds its way underneath a mountain range, through the St. Paul Underground River Cave, and then goes out into the South China Sea. The journey through the cave system alone is 24 kilometers long.
The entire area where the Underground River is located is actually a national park and a model of biodiversity. More than 800 plant species, including almost 300 trees, 195 bird species, 30 mammals, 19 reptiles, and eight bat species call this area home.
The park has a range of forest formations representing eight of the thirteen forest types found in tropical Asia, namely forest over ultramafic soils, forest over limestone soils, montane forest, freshwater swamp forest, lowland evergreen tropical rainforest, riverine forest, beach forest, and mangrove forest. Researchers have identified more than 800 plant species from 300 genera and 100 families.
These include at least 295 trees dominated by the dipterocarp species. In the lowland forest, large trees such as the Dao, Ipil, Dita, Amugis, and Apitong are common.
Birds comprise the largest group of vertebrates found in the park. Of the 252 bird species known to occur in Palawan, a total of 165 species of birds were recorded in the park. This represents 67% of the total birds and all of the 15 endemic bird species of Palawan.
There are also some 30 mammal & 19 species of reptiles species that have been recorded. Most often observed in the forest canopy and along the shoreline feeding during low tide is the long-tailed macaque, the only primate found in the area.