The Mammalia of Timor as well as those of the other islands of the group are exceedingly scanty, with the exception of bats. These last are tolerably abundant, and no doubt many more remain to be discovered. Out of fifteen species known from Timor, nine are found also in Java, or the islands west of it; three are Moluccan species, most of which are also found in Australia, and the rest are peculiar to Timor.
The land mammals are only seven in number, as follows: 1. The common monkey, Macacus cynomolgus, which is found in all the Indo-Malayan islands, and has spread from Java through Bali and Lombock to Timor. This species is very frequent on the banks of rivers, and may have been conveyed from island to island on trees carried down by floods. 2. Paradoxurus fasciatus; a civet cat, very common over a large part of the Archipelago. 3. Felis megalotis; a tiger cat, said to be peculiar to Timor, where it exists only in the interior, and is very rare. Its nearest allies are in Java. 4. Cervus timoriensis; a deer, closely allied to the Javan and Moluccan species, if distinct. 5. A wild pig, Sus timoriensis; perhaps the same as some of the Moluccan species. 6. A shrew mouse, Sorex tenuis; supposed to be peculiar to Timor. 7. An Eastern opossum, Cuscus orientalis; found also in the Moluccas, if not a distinct species.
The fact that not one of these species is Australian or nearly allied to any Australian form, is strongly corroborative of the opinion that Timor has never formed a part of that country; as in that case some kangaroo or other marsupial animal would almost certainly be found there. It is no doubt very difficult to account for the presence of some of the few mammals that do exist in Timor, especially the tiger cat and the deer. We must consider, however, that during thousands, and perhaps hundreds of thousands of years, these islands and the seas between them have been subjected to volcanic action. The land has been raised and has sunk again; the straits have been narrowed or widened; many of the islands may have been joined and dissevered again; violent floods have again and again devastated the mountains and plains, carrying out to sea hundreds of forest trees, as has often happened during volcanic eruptions in Java; and it does not seem improbable that once in a thousand, or ten thousand years, there should have occurred such a favourable combination of circumstances as would lead to the migration of two or three land animals from one island to another. This is all that we need ask to account for the very scanty and fragmentary group of Mammalia which now inhabit the large island of Timor. The deer may very probably have been introduced by man, for the Malays often keep tame fawns; and it may not require a thousand, or even five hundred years, to establish new characters in an animal removed to a country so different in climate and vegetation as is Timor from the Moluccas. I have not mentioned horses, which are often thought to be wild in Timor, because there are no grounds whatever for such a belief. The Timor ponies have every one an owner, and are quite as much domesticated animals as the cattle on a South American hacienda.