The wealth of flora and fauna in the Riau Islands is also very diverse. The "Lutjanus gibbus" and "Piper betle" are the fauna and flora symbol of the Riau Islands province respectively. The Humphead wrasse ("Cheilinus undulatus"), which is an endangered type of fish, inhabits the Natuna Sea in the northern part of the province. In addition, Dugongs also live in the waters around the island of Bintan. Some other rare animals are the Tarsius, and the Natuna Island surili ("Presbytis natunae"), native to the island of Natuna. The Natuna Island surili is one of the 25 most endangered primates on Earth. Wealth of flora in the province includes the "Oncosperma tigillarium", dragon fruit, areca nut and the rare udumbara plants that live on the Engku Puteri Plateau, Batam Center. The Riau Islands has 2 nature reserves, namely Pulau Burung Nature Reserve and Pulau Laut Nature Reserve.