Although the Philippines are commonly held to form an eastern extension of the Indo-Malayan sub-region, there is a large amount of specialization in the fauna of the islands eastward of the Palawan group. Mammals are scarce.
Balabac, Palawan and the Calamianes show a very strong Bornean element.
Bering Sea is bounded by the Alaskan Peninsula and the chain of the Aleutian Islands; the sea of Okhotsk is enclosed by the peninsula of Kamchatka and the Kurile Islands; the Sea of Japan is shut off by Sakhalin Island, the Japanese Islands and the peninsula of Korea; the Yellow Sea is an opening between the coast of China and Korea; the China Sea lies between the Asiatic continent and the island of Formosa, the Philippine group, Palawan and Borneo.
Deer are absent in Palawan, Tawi Tawi, Tablas, Romblon, Sibuyan and Siquijor.
It formerly included the whole of northern Borneo and southern Palawan, and stretched down the west coast as far as Sambas.
The edentates are represented by the pangolin (Manis sp.?) of the Palawan group. In the seas are found the dolphin, cachalot and dugong.
The Philippines, politically speaking, and the Philippines, zoologically speaking, are not identical areas; Balabac, Palawan and the Calamianes being characterized by the occurrence of numerous Bornean forms which are conspicuously absect from the remaining islands.
Very large flying-squirrels are found in Palawan and Mindanao.