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New sci­en­tific research could help to pro­tect tigers (Pan­thera tigris) from extinc­tion. The find­ings indi­cate that tigers should be clas­si­fied as only two sub­species, while up to now nine sub­species are rec­og­nized. This will have a sig­nif­i­cant impact on species con­ser­va­tion since man­age­ment efforts and breed­ing pro­grammes can now be organ­ised in a sim­pler, more flex­i­ble and effec­tive way. The results have been pub­lished on in the sci­en­tific open access jour­nal “Sci­ence Advances”.

The com­pi­la­tion and detailed analy­sis of the most com­pre­hen­sive dataset for tigers ever assem­bled allowed sci­en­tists from the Ger­man Leib­niz Insti­tute for Zoo and Wildlife Research (IZW), National Muse­ums Scot­land, the Selandia Col­lege in Den­mark and the Nat­ural His­tory Museum of Den­mark in Copen­hagen to carry out a crit­i­cal eval­u­a­tion of the nine puta­tive tiger sub­species. They found that most of these sub­species were much more sim­i­lar to each other than pre­vi­ously known. Only two tiger sub­species could be clearly dis­tin­guished: The “Sunda tiger“ (Pan­thera tigris sondaica), for­merly from Suma­tra, Java and Bali and the “Con­ti­nen­tal tiger” (Pan­thera tigris tigris) from main­land Asia. From the per­spec­tive of con­ser­va­tion, the north­ern pop­u­la­tion of the “Con­ti­nen­tal tiger” (the Amur or Siber­ian tiger) should be treated as a dis­tinct con­ser­va­tion man­age­ment unit from the south­ern pop­u­la­tions, since it is adapted to dif­fer­ent envi­ron­men­tal conditions.

For the first time mul­ti­ple trait datasets of the six liv­ing and three extinct tiger sub­species described so far were com­pared. The mor­phol­ogy of more than 200 tiger skulls as well as the col­oration and stripe pat­terns of more than 100 tiger skins were com­pared with mol­e­c­u­lar genetic data and eco­log­i­cal and life his­tory traits. The results did not sup­port the dis­tinc­tion of nine sub­species pre­vi­ously described for tigers. Only the Sunda tiger from the islands of Suma­tra, Java and Bali could be clearly and unam­bigu­ously dis­tin­guished from pop­u­la­tions of the Con­ti­nen­tal tiger. These detailed analy­ses also lend fur­ther sup­port to the idea that there was a mas­sive pop­u­la­tion decline of tigers after the super-​eruption of the Toba vol­cano on Suma­tra about 73,000 years ago. Tigers may have only sur­vived in a sin­gle refugium in South China, from where all mod­ern tigers then originated.

World­wide there is sig­nif­i­cantly more con­cern about and money spent on the con­ser­va­tion of tigers than on any other indi­vid­ual wildlife species. How­ever, fewer than 4,000 tigers roam around the forests of Asia — a his­tor­i­cally low num­ber. For the tiger to sur­vive at all, these small and shrink­ing pop­u­la­tions require active con­ser­va­tion man­age­ment. The dis­cov­ery that only two tiger sub­species exist paves the way for new con­ser­va­tion man­age­ment options in that global pro­tec­tion efforts can now be imple­mented more flex­i­bly and effectively.

“For exam­ple, tiger pop­u­la­tions in South China and Indochina have been reduced to such low num­bers that — if each con­tinue to be clas­si­fied as sep­a­rate sub­species — they would likely face extinc­tion”, explained Dr Andreas Wilt­ing. The new tiger clas­si­fi­ca­tion allows for the com­bined con­ser­va­tion man­age­ment of these pop­u­la­tions and the Malaysian and Indian tiger, as all four pop­u­la­tions from the south­ern part of con­ti­nen­tal Asia can now be man­aged as a sin­gle con­ser­va­tion unit. “The results of our col­lab­o­ra­tive research offer an excit­ing, prag­matic and more flex­i­ble approach to tiger con­ser­va­tion. Now we can plan the restora­tion of wild tiger pop­u­la­tions with con­fi­dence, know­ing that there is a sound sci­en­tific under­pin­ning to tiger tax­on­omy”, says Andrew Kitch­ener from National Muse­ums Scot­land. Kitch­ener sug­gested this new clas­si­fi­ca­tion already in his chap­ter on ‘tiger dis­tri­b­u­tion, phe­no­typic vari­a­tion and con­ser­va­tion issues’ in the book Rid­ing the Tiger (edited by Sei­den­sticker, Christie and Jack­son — 1999).

(Source: Forschungsver­bund Berlin e.V. press release, 26.06.2015)