Tiger taxonomy is complicated
In 1999, numerous tiger subspecies in continental Asia were called into question. Tigers from different places exhibit similar morphologies, and it is thought that gene flow between populations in those regions was conceivable during the Pleistocene. As a result, it was suggested that just two subspecies be recognized as legitimate, namely P. t. tigris in mainland Asia and P. t. spondaic in the Greater Sunda Islands and maybe in Sundaland.
The Siberian and Caspian tiger populations are in the northern clade of the nominate subspecies P. t. tigris, while the remaining populations of continental tigers are in the southern clade. Since the revision of felid taxonomy in 2017, the extinct and surviving tiger populations in continental Asia have been grouped under P. t. tigris.
The Caspian, Indochinese, Malayan, Siberian, and South China tigers are also members of P. tigris tigris, which contains the Bengal tiger. It was formerly thought to be a subspecies. Although it could appear like a downgrade, the taxonomic details have minimal bearing on Bengal tigers' long-standing cultural cachet and do not lessen the significance of any of these populations.
