The bison - or buffalo - are under special protection from hunters amid rising concern over wolf attacks.
Two bison calves born in 2012 are seen as particularly vulnerable to wolf attacks. Picture: Lenskie Stolby Nature Reserve, Yakutia
The threatened animals were airlifted to the Sakha Republic - also known as Yakutia - from Alberta in Canada in recent years.
'Local hunters are guarding two nurseries that are a home to about 100 animals,' said Andrei Popov, an official at the republic's Nature Protection Ministry.
The wood bison, anyway a threatened species, were brought to Siberia to boost the animal's long term chances of survival. Some 10,000 years ago, the related steppe bison roamed this part of sub-Arctic Russia. But the 800 kilogram creatures are powerless against attacks by packs of wolves.
Two bison calves born in 2012 are seen as particularly vulnerable to wolf attacks.
This region in Siberia - and others - have seen unprecedented attacks this winter by wolves on herds of both reindeer and horses. But it is clear the bison are also in jeopardy. A state of emergency was declared in the republic and teams of hunters are now engaged on a purge of the wolves with the government ordering a cull in the population from an estimated 3,500 to only 500.
Hunters are on financial incentives to slaughter the wolves.
A fall in polar hare numbers has led to wolves switching to other food sources, say zoologists.
More than 16,000 reindeer and over 300 horses were lost last year.
The bison were flown in to Sakha by a heavy Russian transport aircraft between 2006 and 2011.
The aim is for the population to become self-sustaining and then to release them to the wild.
'Bison haven't been present in that part of the world for over 10,000 years', said Todd Shury, a Parks Canada wildlife veterinarian involved in the bison relocation in 2011.
Rescue effort underway to provide emergency feeding sites for the helpless animals, with the wild boar population also in trouble.
The world's fluffiest feline get a first-in-the-world scientific zone where the endangered wildcats will be protected and studied.
Shoreline on remote island retreats by 74 metres in seven years due to increased wave power of unfrozen sea, and thawing permafrost.