The mammalian fauna of the Philippines is a remarkable assemblage of species that occur from the depths of the sea to the tops of cloud-enshrouded mountains. The data provided here are brief and limited, but they provide a clear overview of this fauna. Although we refer the reader to recent summaries of zoogeography and conservation status for details (Heaney, 1986, 1991b, 1993; Heaney et al., 1997), several key features will be apparent from perusal of this listing.

     First, the terrestrial fauna of the Philippines is divided into a series of centers of endemism.
These centers correspond to the islands that existed in the Philippines during periods of glacial development in high-latitude regions and consequent low sea level worldwide. Everyone of these ice-age islands that has been investigated, including the tiny islands of Camiguin and Sibuyan, supports at least two endemic species, and most islands have many more endemic species (Heaney, 1985b, 1986, 1991b, 1993). The sole exception to this pattern is Siquijor, which has no endemic species, but also has virtually no native vegetation remaining (Lepiten, 1995).

     Second, native terrestrial mammalian species occur at every elevation and in every type of forest habitat that remains in existence in the country (e.g., Heaney et al., 1989; Rickart, 1993; Rickart et al., 1991). On the other hand, few native species are known to survive in deforested habitats, and many native species cannot survive in disturbed forest (Heaney, 1993; Heaney & Utzurrum, 1991).

     Third, at least 50 species of terrestrial mammals currently are known to be threatened to varying degrees, some critically so. Many others that are poorly known at present are certain to be added to this number as more information becomes available (Heaney, 1993; Heaney & Utzurrum, 1991; Oliver & Heaney, 1996; Utzurrum, 1992). Endangered species occur in every faunal region and in all types of natural (undisturbed) habitat. Populations of most endemic species have declined significantly, the vast majority as a result of forest habitat destruction. It is clear that forest destruction has been and remains at present the primary conservation problem on land in the Philippines. Additionally, overhunting has had a severe impact on most large terrestrial species and several marine species, and disturbance and destruction of caves has had a major impact on many species of bats (Utzurrum, 1992). Whale hunting in the Bohol Sea by fishermen from Pamilacan, Bohol, and Camiguin has almost completely wiped out the Philippine population of Bryde's whale. This population is part of the Southeast
Asian group found to be morphologically and genetically different from all other Bryde's whales and may deserve recognition as a separate species (Perrin et al., 1996b; Dizon et al., 1996).

     Fourth, the rich marine mammal fauna is associated with the archipelagic nature of the country, which has resulted in the usual bathymetric topography of its marine environment. Small islands are surrounded by very deep oceanic waters (the Philippines have some of the deepest waters in the world), and conversely, deep oceanic waters are often isolated from each other by narrow, shallow sills as well as by islands. This situation has resulted in complex marine habitats and affected the distribution of cetaceans. It is common to find cetaceans that are considered to be "offshore oceanic species" (e.g., Fraser's dolphin, Lagenodelphis hosei) only 30 m off an island in the Philippines, which makes them "coastal" species as well. This has also changed the whole suite of species associations and assemblages usually seen elsewhere, making the Philippine situation quite exceptional.

     Fifth, the mammalian fauna of many parts of the Philippines, both marine and terrestrial, remains poorly known. Detailed, extensive, and quantitative field studies are crucial in enhancing knowledge of the fauna. Superficial study will not yield information on rare or elusive species, nor will it provide the basic data required for long-term management decisions.

     The data presented in this paper paint a brief picture of one of the most remarkable mammalian faunas on Earth: giant bushy-tailed rats, dwarf buffalos, bats with nearly 6-ft. wingspans, burrowing rodents with white stripes, and "flying lemurs" that neither fly nor are lemurs. These species form a remarkable community of animals that may be viewed as forming a vast natural experiment in the evolution and maintenance of mammalian diversity. Uncovering the story of the origin and ecology of this diversity has provided one of the major incentives to us in carrying out the research on which much of this synopsis is based. A part of the picture, however, is recent and continuing destruction of forests and reefs, leaving too many species with only a few places that can sustain them. It is neither an exaggeration nor unwarranted melodrama to say that unless effective action is taken soon to protect the native habitats of these animals, one of the most remarkable stories of mammalian evolution on Earth will end, and an irreplaceable part of the Filipino heritage will be lost forever. It is our hope that this paper will assist in the process of developing effective protection for the environment of the people and the wildlife of the Philippines, solidly based on knowledge, and dedicated to providing a stable environment for all.