Sibutu Passage is a deep channel some 18 miles (29 km) wide that separates

Borneo Borneo (; id, Kalimantan) is the third-largest island in the world and the largest in Asia. At the geographic centre of Maritime Southeast Asia, in relation to major Indonesian islands, it is located north of Java, west of Sulawesi, and eas ...

from the Sulu Archipelago. It has a deep sill allowing entry of deep water into the Sulu basin while connecting the

Sulu Sea The Sulu Sea ( fil, Dagat Sulu; Tausug: ''Dagat sin Sūg''; Chavacano: ''Mar de Sulu''; Cebuano: ''Dagat sa Sulu''; Hiligaynon: ''Dagat sang Sulu''; Karay-a: ''Dagat kang Sulu''; Cuyonon: ''Dagat i'ang Sulu''; ms, Laut Sulu) is a body o ...

with the

Sulawesi Sea The Celebes Sea, (; ms, Laut Sulawesi, id, Laut Sulawesi, fil, Dagat Selebes) or Sulawesi Sea, of the western Pacific Ocean is bordered on the north by the Sulu Archipelago and Sulu Sea and Mindanao Island of the Philippines, on the east by ...

that feeds from the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

by the

Mindanao Current The Mindanao Current (MC) is a southward current in the western Pacific Ocean that transports mass and freshwater between ocean basins. It is a low-latitude western boundary current that follows the eastern coast of the Philippine island group a ...

. Although

H. Otley Beyer Henry Otley Beyer (July 13, 1883 – December 31, 1966) was an American anthropologist, who spent most of his adult life in the Philippines teaching Philippine indigenous culture. A.V.H. Hartendorp called Beyer the "Dean of Philippine ethnolo ...

argued in favor of a settlement of the Philippines across

land bridge In biogeography, a land bridge is an isthmus or wider land connection between otherwise separate areas, over which animals and plants are able to cross and Colonisation (biology), colonize new lands. A land bridge can be created by marine regre ...

s during the last ice age, modern

bathymetric Bathymetry (; ) is the study of underwater depth of ocean floors (''seabed topography''), lake floors, or river floors. In other words, bathymetry is the underwater equivalent to hypsometry or topography. The first recorded evidence of water de ...

soundings have shown that the centers of the Sibutu Passage and the

Mindoro Strait The Mindoro Strait ( tgl, Kipot ng Mindoro) is one of the straits connecting the South China Sea with the Sulu Sea in the Philippines. It separates Mindoro Island from Busuanga Island (one of the Calamian Islands of Palawan Province). Located bet ...

are both deep enough that they probably still existed at that time, although the Sulu and other

Philippine Islands The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

beyond were one connected island. If verified, therefore, the

Callao Man ''Homo luzonensis'', also locally called "Ubag" after a mythical caveman, is an extinct, possibly pygmy, species of archaic human from the Late Pleistocene of Luzon, the Philippines. Their remains, teeth and phalanges, are known only from Calla ...

would have needed to have crossed open sea to reach the islands.

References

* ''Philippine Islands Sailing Directions'', third edition of the bulletin prepared in the office of the

U.S. Coast and Geodetic Survey The National Geodetic Survey (NGS) is a United States federal agency that defines and manages a national coordinate system, providing the foundation for transportation and communication; mapping and charting; and a large number of applications ...

Manila Manila ( , ; fil, Maynila, ), officially the City of Manila ( fil, Lungsod ng Maynila, ), is the capital of the Philippines, and its second-most populous city. It is highly urbanized and, as of 2019, was the world's most densely populate ...

by Harry L. Ford, nautical expert (Washington, DC: Bureau of Printing, 1906), p. 171 * Lambert Anthony B. Meñez, Cesar L. Villanoy and Laura T. David. "Movement of Water Across Passages Connecting Philippine Inland Sea Basins" (Marine Science Institute, University of the Philippines, November 6, 2006)

External links

Map of Sibutu Passage (channel), Philippines
Encarta - MSN
Malaysia Map - Malaysia Satellite Image
- Geology.com Straits of the Philippines Straits of Malaysia Malaysia–Philippines border International straits {{Philippines-geo-stub