DISTRIBUTION Birgus latro is widely distributed throughout the Western Pacific and eastern Indian Oceans, occurring almost exclusively on oceanic islands or on small offshore islets adjacent to large continental islands (2). However, although it has a wide geographic spread, it probably does not occur on all atolls since those that are dry do not provide enough food (31). In the Indian Ocean, it is found on islands south of the equator (21). Still occurs abundantly on Aldabra (f3) but is extinct on almost all the islands in the Seychelles group (23); occurs on some of the numerous small islands off the Tanzanian coast (5); in the Andaman and Nicobar Islands now found only on South Sentinel Island (21,22) and at Galathea Bay where it was said to be common in 1967 (350); formerly occurred on Mauritius but exterminated in the second half of the 19th century; in 1939 almost exterminated in the Keeling Islands (except for uninhabited North Keeling I) (21); in the Chagos Archipelago, found on both of the northern atolls and on most of the islands of the Great Chagos Bank (25); widely distributed on Christmas Island f). Has not been recorded from the East African mainland coast, the Maldives and Laccadives, the islands near Peninsula Malaysia and Sumatra, the western part of the Malay Archipelago nor the islands in the South China Sea (21). In 1981, found on Sipadan Island, about 30 miles (48 km) off the east coast of Sabah, Malaysia (33). In 1939 was still present in parts of Indonesia, the Philippines and Taiwan (21). Currently is found on Olango Island, off Mactan (Cebu) in the Philippines (28). In Indonesia it has recently been reported from the Togian Islands, Central Sulawesi (24) and in 1963 from the north coast of Irian Jaya (15). A detailed account of its distribution in the 1950s on the small islands off the north coast of Irian Jaya is given in (46). In Papua New Guinea has been reported from Rantan and Sae Islands (32) and Los Negros Island (30) in Manus Province. In the Pacific found in Fiji and the Marshall Islands but not in the Hawaiian group. Wake or Midway (13,31). Recorded from Gardner Island in the Phoenix Islands (7), the Juice Islands and Tuamotus (31), Fanning Island (14), the Marianas (2) and Vanuatu (36,37). POPULATION Unknown. HABITAT AND ECOLOGY Almost entirely terrestrial and drowns in water (1 1,44), although the female has to return to the sea to release her eggs and crabs may go to the beach and drink seawater to maintain their salt balance (2,26). On Guam they are most typically found in coastal limestone forests where they establish burrows within the porous, solution-pitted limestone substrate. On some islands in the northern Marianas they occupy burrows dug in the soil or in the interstices of the boulder-cobble shorelines (2). On Olango Island in the Philippines, they live in burrows in coral rock in thick undergrowth. These are 05-1 m in diameter and 1-2 m deep, and may extend 4-6 m in a horizontal direction (28). On barrier reef islands crabs have been found to live in shallow burrows in the substrate or hidden among Pandanus roots and fallen coconut fronds. On such islands Coconut Crabs may occur throughout the island, but on larger high islands, such as Guam, they are rarely found in the interior (2). On Aldabra the species is most abundant in the sandy coconut grove at Anse Mais and in damp Pandanus thickets on South Island, but is also found in the barren coastal champignon and throughout the plain. Normally the crabs inhabit rock crevices, although they can burrow in sand (42). On Christmas Island, the Coconut Crab occurs from the beach through the shore terrace to the highest parts of the plateau. Its distribution is uneven and some areas are apparently avoided. Crabs frequently collect together in groups of a dozen or more (10). Larger crabs may inhabit the best areas of an island, with sandy soil for burrowing and abundant coconut palms (13). 3t0