Polar bear diet switches from seals to eggs

Polar bear diet switches from seals to eggs

For daily news stories, visit newscientist.com/news POLAR bears may be ditching seafood in favour of scrambled eggs as the heat rises in the Arctic, ...

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For daily news stories, visit newscientist.com/news

POLAR bears may be ditching seafood in favour of scrambled eggs as the heat rises in the Arctic, melting sea ice. A changing coastline has made it harder for the predators to catch the seals they favour and is pushing them towards poaching goose eggs. This is according to a team led by Charmain Hamilton of the Norwegian Polar Institute that monitored polar bears and seals before and after a sharp decline in sea ice in 2006 in the Norwegian archipelago of Svalbard. The team attached tracking devices to 60 ringed seals as well as 67 polar bears, which allowed them to see how the ice loss affected their movements. Before the melt, when they were hunting on stable sea ice, the polar bears had a big advantage over their favoured prey. However, on a melting coastline punctuated by broken-up icebergs, the odds become stacked in the seals’ favour. In response, the bears are retreating from the coast – and away from the seals. The tracking devices show them wandering greater distances in search of alternative land-based food. The bears also spend a lot more time near bird nesting grounds, which suggests eggs have become a significant food source. This shift could devastate nesting bird populations (Journal of Animal Ecology, doi.org/b63h). “It takes on average 30 seconds to locate a nest and 60 seconds to eat the eggs,” says Jouke Prop at the University of Groningen, the Netherlands. Previous research found that affected bird populations can slump by up to 90 per cent. As the bears move on to eating bird eggs, any drop in geese populations could bring wider ecological changes. “If numbers decline – which is to be expected – this will have an impact on the whole terrestrial ecosystem,” says Prop. “For example, Arctic foxes depend on young geese as food; reindeer food intake is facilitated by geese grazing the tundra.” Thom Hoffman n


Polar bear diet switches from seals to eggs

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