Grizzly bears in Alaska have stopped eating salmon and are instead chewing on berries which are ripening earlier due to climate change. 

Rising temperatures have led to elderberries on Kodiak Island being ready to eat in early summer, just as local rivers are teeming with sockeye salmon.

Bears traditionally feast on salmon in the early salmon before swapping to berries later in the season - but climate change has thrown that schedule off kilter. 

"It's essentially like if breakfast and lunch were served at the same time and then there's nothing to eat until dinner," Oregon State University biologist William Deacy told The Telegraph. 

Dr Deacy and others studied bear's behavioural patterns and found that they were ignoring salmon in streams and instead gobbling down berries, which are lower in protein and are more easily broken down by the bears.

The change in diet has researchers worried because it could upset the delicate ecoysystem that has developed in the area. 

Forests close to salmon-filled streams appear to be suffering, with no more fish carcasses left on the ground to decompose and enrich the nutrient-deficient soils. 

The research study was published in Proceedings of the National Academy of Sciences.