Are there many subspecies of tiger, or only two? A correct accounting is the only way to preserve what is left of the animal’s genetic diversity, some scientists say.
A Sumatran tiger at the Ragunan Zoo in Jakarta, Indonesia. Sumatran tigers were the first to evolve from all tigers’ common ancestor. Credit Romeo Gacad/Agence France-Presse — Getty Images
Fewer than 4,000 tigers remain in the wild. New research aims to give conservationists an improved understanding of their genetics in order to help save them.
After years of debate, scientists report in the journal Current Biology that tigers comprise six unique subspecies. One of those subspecies, the South China tiger, survives only in captivity.
“The results presented in this paper are important because they contradict the currently accepted international conservation classifications for tigers,” said Uma Ramakrishnan, a molecular ecologist at the National Center for Biological Sciences in Bangalore, India, who was not involved in the study.
A system recently proposed by some scientists that would classify the world’s tigers into two subspecies would harm the world’s remaining tigers rather than benefit them, said Shu-Jin Luo, a geneticist at Peking University who led the study. Preserving what is left of tigers’ genetic diversity will require ensuring that all remaining subspecies are taken into account, she and her co-authors argue.
“If you think that all tigers are genetically homogeneous, you might say if you lose the Amur tiger, you still have the Bengal tiger — and that’s O.K. because they’re very similar,” Dr. Luo said. “But that’s not O.K., because now we know that tigers are not all alike.
Dr. Luo hopes that their new findings put to rest a decade-long debate over whether tigers constitute six, five or two subspecies. In 2004, she and her colleagues first presented research that tigers constitute six living subspecies, based on partial genomic analyses. But other researchers soon challenged the findings.
The latest analysis confirmed six living subspecies: Bengal, Amur, South China, Sumatran, Indochinese and Malayan. Scientists also believe that three additional subspecies — Caspian, Javan and Bali tigers, described in the 1930s — already have been lost to extinction…