A preliminary 2021 study published by Brook "et al". compiles many of the alleged sightings of thylacines in Tasmania throughout the 20th century and claims that contrary to beliefs that thylacines went extinct in the 1930s, the Tasmanian thylacine may have actually lasted throughout the 20th century with a window of extinction between the 1980s and the present day, with the likely extinction date being between the late 1990s and early 2000s. The study claims that the reason behind the apparent lack of confirmed sightings during this wide and relatively recent time range is the lack of wide deployment of camera traps (which have been used to rediscover other elusive carnivores such as the Zanzibar leopard) in Tasmania until the early 21st century, by which time the thylacine would be extinct or very nearly so. This study has not yet been peer-reviewed.