Rubondo Island National park is Tanzania’s only park on Lake Victoria. The island attracts a small number of visitors each year, mainly game fishermen and bird enthusiasts. Rubondo Island is located in the south-western corner of Lake Victoria, Tanzania. Rubondo Island is about 150 km (93 mi) west of Mwanza. The main island, Rubondo is 237 km2 in size. The island protects another 11 islets, none much larger than 2 km2. These 10 islands form the Rubondo Island National Park covering an area of 456.8 km2 (176.4 sq mi). Lake Victoria is 1,134 metres above sea level.
The highest point on Rubondo is the Masa Hills in the far south, at an elevation of 1,486m (350m above the level of the lake). The main island measures 28 km from north to south and is 3–10 km wide. Rubondo Island is on a rift in the lake. Rubondo essentially consists of a partially submerged rift of four volcanically formed hills, linked by three flatter isthmuses. The island has no rivers and the soil is volcanic. The habitat is mixed evergreen and semideciduous forest, which covers about 80% of the island’s surface area with common species including Croton sylvaticus, Drypetes gerrardii, and Lecaniodiscus fraxinifolius, and often with a dense understory of lianas, or woody vines. The forest is interspersed with patches of open grassland and, all but restricted to the Lukaya area, acacia woodland. The eastern lakeshore is characterised by rocky areas and sandy beaches whilst the western shore supports extensive papyrus swamps, lined with date palms .
Over a four-year period (1966–1969) Professor Bernhard Grzimek of the Frankfurt Zoological Society (FZS) released 17 chimpanzees in four cohorts onto Rubondo Island. The first cohort of chimpanzees arrived in Dar es Salaam aboard the German African Line’s steamship Eibe Oldendorff on 17 June 1966 (Standard Newspaper Tanzania, 1966). The animals had no rehabilitation or pre-release training. The chimpanzees were all wild-born and purportedly of West African descent, although there are no records of specific country of origin for the majority of released individuals. The founder chimpanzees had spent varying periods, from 3.5 months to 9 years, in captivity in European zoos or circuses before their release. The chimpanzees after one year were able to find and eat wild foods and construct nests for sleeping, and have now reverted to an unhabituated state characteristic of wild chimpanzees. From 16 founders spopulation has now grown to around 40 individuals (estimate based on nest counts).
In addition to chimpanzees, seven other species were introduced to the island: Roan antelope (Hippotragus equinus) and rhinoceros (Diceros bicornis) both now extinct, Suni antelope (Neotragus moschatus), elephants (Loxodonta africana), twelve giraffes (Giraffa camelopardalis), 20 black-and-white colobus monkeys (Colobus guereza), and African grey parrots (Psittacus erithacus) confiscated from illegal trade; see.