Bali is a so-called continental island, that is to say, an island which sits on the continental shelf and is typically situated close to the mainland, in this case java. Surrounded by shallow seas,  it is periodically connected to the mainland at times of lowered sea levels which occur  whenever there are ice ages. The later circumstances allow an exchange of species—both plant and animal- with the mainland, with the result  that the native flora and fauna of the  island generally resembles that of the mainland, though the diversity of island species is usually less, Bali is no exception to this rule, though the island does have at least  one known endemic species, that is  to say, a species which is unique to Bali and found nowhere else in the world. This is the famed Bali starling (Lucosparrothschildi) which was  only discovered by Western science as recently as 1911.In the past, there was also a subspecies of tiger (Puntheratigrisbalica), but that has become extinct, a fate which also threatens the Bali starling.