Two distinct populations of grey wolves have been found living side-by-side in British Columbia, Canada.
The research built on the knowledge of indigenous people who had distinguished between the mainland "timber wolf" and island "coastal wolf".
Scientists compared DNA from wolf faeces to determine if the two groups were different.They say their findings show that different environments can influence genetic changes.
The team, based at the University of Victoria, reported their research in the journal BMC Ecology. The study focused on an area of the central coast of British Columbia known as Bella Bella, which includes a mainland landmass separated from five islands by water. The researchers collaborated with people from the indigenous Heiltsuk First Nation who have studied the wolves for nearly a decade.
Photos: Chris Darimont; Guillaume Mazille
"He (Mr Starr) asked if we were going to study the 'timber wolves' of the mainland or the 'coastal wolves of the islands'," Dr Darimont said. "I thought that was peculiar because the state of science at the time told us that there really shouldn't be differences within wildlife populations across such a short distance, especially as wolves are fantastic swimmers.
"Chester explained that timber wolves are creatures of the mainland, who liked the more mountainous habitat and the plentiful deer and other terrestrial foods, but the island wolves were smaller seafood lovers. He knew they were different."
But the elder's idea did not fit well with the current understanding of wolf biology and the researchers initially dismissed it. Since then, evidence has shown genetic differences within closely-occurring populations of sea turtles, fish and mammals, including wolves. The team went on to study 116 individual grey wolves living in the Bella, Bella area and identified a genetic difference between mainland and island wolves.
"As scientists we should be sceptical, not dismissive. Earlier in my career, I had assumed that ecological knowledge could only come from science. I was wrong, and it's exciting to learn from this and similar experiences with indigenous colleagues," Dr Darimont said.
The scientists believe the extreme differences between the mainland and island habitats are responsible for the changes in genetics. Their data suggests that island wolves are now more likely to breed with other island wolves than neighbouring mainland wolves.
"What is special here is that the gradient exists over such short distances, a few hundred metres to a couple of kilometres, which is easily swimmable. However the ecological differences are sharp and that's what set in motion this genetic cline."
The team say their findings present opportunities for further research and could help conservation attempts by offering detailed information about the habitats of animals in neighbouring areas.