INTERNATIONAL NEWS - High-tech collar tracking collars on nine female polar bears have measured the animals' efforts to find food on the diminishing Arctic ice.

The collars recorded video, locations and activity levels over 11 days, while metabolic tracers allowed scientists to work out how much energy bears used.

This revealed that the animals were unable to catch enough prey to meet their energy needs.

The team say wild bears have higher metabolic rates than thought.

Moreover, climate change appears to be having dramatic effects on the Arctic sea ice, forcing polar bears to move greater distances as they hunt, and making it harder for them to catch prey.

The vision of a polar bear plucking a vulnerable seal off an ice floe is something familiar to wildlife documentary fanatics. Earlier this winter though, an image of an emaciated polar bear went viral, with many asking if this was the telltale image of climate change.

The authors of this study, published in the journal Science, point out that the animals do now need to travel further to find seals, and that this is likely to be an "important factor explaining declines in their body condition and survival" of polar bears.

Read more on BBC.