'Baa'd news for Yukon's Stone sheep: they're not actually Stone sheep

Call it a case of mistaken identity. Thousands of Thinhorn sheep in southern Yukon — once believed to be Stone sheep — are actually Dall sheep, researchers say.

Southern Yukon's population of Stone sheep is actually a population of Dall sheep, researchers say

Stone (or Stone's) sheep tend to be darker in colour than Dall sheep. Both are subspecies of Thinhorn sheep. ( BC MLFNRO and Environment Yukon)

Call it a case of mistaken identity.

Researchers have discovered that Yukon's small population of Stone sheep has been misidentified for years — the animals should in fact be classified as Dall sheep.

That means that the overall population of Stone sheep (also known as Stone's sheep) in Western Canada is about 20 per cent less than was previously thought. 

Both Stone and Dall sheep are subspecies of Thinhorn sheep. Dall (or Dall's) sheep are commonly whiter in colour and Stone sheep tend to be a darker brown. 

Researchers from the University of Alberta used DNA markers to correctly identify about 2,800 animals in the Pelly and Cassiar mountains in southern Yukon, as Dall sheep.

"They have always been classified as Stone's sheep. The previous classification is, as long as you have any kind of dark colourization, you are considered a Stone's sheep," said Zijian Sim, a PhD student in the department of biological sciences at the University of Alberta. 

'We only found one sheep in the Yukon that we would consider a Stone's sheep. Only one, and before they thought there were thousands,' says researcher Zijian Sim. ( BC MLFNRO and Environment Yukon)

"But what our genetic evidence is finding is that these sheep, although coat-colourwise they might resemble Stone's sheep to the south, they are more related genetically to Dall's sheep in the north."

Stone sheep are only found in northern B.C. and Yukon, although Sim says that may need to be re-thought.

"Now we are finding it's even more restrictive — basically, only in B.C.," he says.

"There might be some Stone's sheep at the tip of the southern Yukon, but in our entire study, and we studied 2,800 rams, we only found one sheep in the Yukon that we would consider a Stone's sheep. Only one, and before they thought there were thousands."

Sim says the new research has prompted the B.C. and Yukon governments to talk about co-managing herds that straddle borders.

Stone sheep are found primarily in northern B.C. (Andrew Kurjata/CBC)


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