The smallest bat in the world is the Philippine bamboo bat (vespertilionid), which belongs to the vespertilionid family. This bat measures about four centimeters (1 1/2 inches) in length and has a wingspan of 15 cm. Approximately, it weighs 1.5 grams (1/20 ounce).
The three-layered virgin forest of Subic Bay and Bataan is home to the world's largest bats: the giant flying fox (Acerodon jubatus) and the golden crown flying fox (Pteropus vampyrus). Over the years, these two species of giant fruit bats have roamed around the 10,000-hectare Subic Forest National Protected Area, which is considered the biggest roosting site of bats in the world.
An ordinary giant flying fox weighs up to 2.5 pounds (1.1 kilograms), heavier than a golden crown flying fox. The golden crown measures six feet in wingspan, the largest among all bats. The giant flying fox and the golden crown are just two of the 15 species of fruit bats in the country.
In other parts of the country, several bat species are now believed extinct. Among them were bare-backed fruit bat or Dobsonia chapmani, which reportedly disappeared from the forests of Negros and Cebu in 1964 and the Panay fruit bat or Acerodon Lucifer which was last seen in 1892. The Philippine tube-nosed bat, Nyctimene rabori of Negros is considered highly endangered. Scientists warned that this breed would disappear before 2015 unless action is taken to protect its remaining population.