Warming bad news for white animals
Animals with white fur are in danger of dying out because climate change is causing a fall in snow cover, leaving them exposed and vulnerable, a new study suggests.
Scientists in Poland have been following the worrying decline of the white-coated weasel, which sheds its tawny covering in the winter for a milky coat, allowing it to blend effortlessly into its icy environment.
But researchers have discovered that between 1997 and 2007, the number of days with permanent snow cover in Białowieza Forest, Poland, halved, from 80 to 40. It means that the creatures are being caught out in an unsuitable environment, where they are easy prey for predators such as foxes and crows.
The team at the Polish Academy of Sciences found that on days when there was little winter snow cover, the number of white-coated weasels captured fell to as low as 20 per cent of the total, suggesting the rest had been killed.
Previously they would have been dominant, because their coats would have given them a survival advantage.
The problem is likely to affect other white-furred mammals and birds living in areas vulnerable to climate change, such as the Arctic fox, as the snow cover increasingly gives way to a landscape of greens and browns.
Scientists have recorded 21 mammal and bird species which turn white in the winter to hide themselves in snowy landscapes, including the mountain hare, the Siberian hamster, the collared lemming, the whitetailed jackrabbit and the willow ptarmigan bird.
Author Dr Karol Zub told the Daily Telegraph: “Definitely the same rules apply to all seasonally moulting mammals and birds.
“According to studies on showshoe hares during periods when hares are colour mismatched, weekly survival probability decreases by 3.3 to 6.5 per cent. This seems not to be a big effect, but the cumulative effect over winter can seriously influence mortality of the species.
“It is probable that in the near future, white weasels and stoats will disappear completely from many areas of Northern Europe and North America.”
The researchers are hopeful the animals will learn to adapt but say they cannot rule out the animals vanishing entirely.