The effective population of the Critically Endangered Siberian tiger is fewer than 14 animals, say scientists.
Although approximately 500 Siberian tigers survive in the wild, the effective population – a measure of the species’ genetic diversity and health – is much lower.
World’s largest cat
The Siberian tiger, also known as the Amur tiger, is the world’s largest cat. It once occurred across much of northern China, the Korean peninsula, and the southernmost regions of eastern Russia.
However, during the early 20th Century, the Siberian tiger was almost driven to extinction, as expanding human settlements, habitat loss and poaching wiped it out from over 90% of its range. By the 1940s, just 20 to 30 individuals survived in the wild.
The new study has identified that this recent ‘genetic bottleneck’ – when the breeding population of Siberian tigers was critically low and the variety of genes being passed on dramatically reduced – has decimated the Siberian tiger’s gene pool.
A more genetically diverse population of animals has a much better chance of survival. For example, it is more likely to have resistance to a variety of diseases and is less likely to succumb to rare genetic disorders.
Very low diversity means any vulnerability to disease or a rare genetic disorder is likely to be passed on to the next generation.
Worryingly low effective population size
Scientists in Russia, Spain and Germany worked together to analyse DNA samples from 15 wild Siberian tigers in the Russian Far East.
They took blood samples from the tigers and looked for certain ‘markers’ – points in the DNA that show whether or not an animal’s parents were very genetically different from each other. The findings are reported in the journal Mammalian Biology.
The results revealed evidence of the genetic bottleneck during the Siberian tiger’s recent history. It appears the Siberian tiger has not recovered from this, denting optimism for the conservation of this iconic animal.
“Our results are the first to demonstrate a quite recent genetic bottleneck in Siberian tigers, a result that matches the well-documented severe demographic decline of the Siberian tiger population in the 1940s”, the researchers wrote in the paper.
“The worryingly low effective population size challenges the optimism for the recovery of the huge Siberian cat.”
Alex Royan, ARKive Species Text Author