Walruses: The friendly, fun-loving, musically talented creatures are under threat from climate change
Jamie Merrill, The Independent 11 Sep 08;
With its bearded face and thick blubber, the walrus isn't the prettiest mammal in the ocean – that distinction is more likely to go to a sleek seal pup or a playful dolphin.
But looks aren't everything, and scientists who work closely with walruses say that they have winning personalities, a great sense of fun and are musical to boot. Now, though, these majestic creatures could be at risk from the effects of climate change.
Divided between the larger and more numerous Pacific walrus and the smaller and rarer Atlantic walrus, the world's walrus population is found at Arctic latitudes across Alaska, Canada, Greenland and western Russia. Here, walruses spend much of their time on and around ice floes, feeding on molluscs. But as temperatures at the North Pole rise, this pack ice is shifting north over deeper waters where the walruses struggle to reach their food.
It seems that anyone who works with walruses soon falls under their spell. Dr Ronald J. Schusterman of the University of California, who has studied them for many years, says that they are all too easy to fall in love with. "The first time I encountered one, I said to myself, 'Wow, these animals are really something else.'" Dr Colleen Reichmuth of the Long Marine Laboratory agrees. "As soon as I started working with walruses, I was really struck by how intriguing they are. They are such social and communicative animals."
Walruses spend about one-third of their time on ice or land, before heading out to sea in search of food. Out of water, they are nearly always found in groups or herds which can reach up to 2,000 in number. They use their tusks, which can grow to 80cm in length, to heave themselves out of the water on to the slippery ice – hence the family name, odobenidae, which in Latin means "those who walk with teeth". "They are very gregarious and social animals who like to hang out together and flop on one another," Dr Schusterman says. "They are very tactile and really like to touch just about anything. When we work with them in captivity, that can be a little intimidating at first, but they really are pussycats."
The bonds between herd members are very strong, and there is anecdotal evidence from Inuits that walruses are extremely nurturing creatures. Older animals have been known to try to protect wounded group members from hunters. "This is really unusual among species with a lower degree of social development. We might expect to see that sort of behaviour in elephants, killer whales or lions, but we don't understand yet why that sort of behaviour might be apparent in walruses," explains Dr Reichmuth.
"We know very little about their reproductive behaviour, but we do know that males have these incredible underwater songs that they produce during breeding season," she says. Using underwater microphones in the walruses' high Arctic habitats, scientists have been able to listen to them use their flesh, muscular lips, tongues, muzzles and noses to sing by striking their flippers against their chests to hit a balloon-like pouch in their trachea to create "songs" with clicks, rasps and bell-like tones, which can be heard up to 16 kilometres away. "Their song is spectacular. Some people call it the bell or gong because it can sounds like a ship's bell. If you had to apply human labels, you might say that walruses are both socially and musically talented," says Dr Schusterman.
But the future is far from rosy for these musical beasts, as the threat of global warming looms over their icy habitat. The most disturbing signs of climate change surfaced in 2004, when a team of climate-change researchers cruising through the Beaufort Sea, north of Alaska, saw walrus calves swimming alone in deep water, far from either ice or land. Crying loudly, they had, it seemed, been separated or abandoned by their mothers as the sea ice retreated north to deeper water. Summer ice cover has been declining since 1980 and last September shrunk to just 1.65 million square miles – almost 40 per cent less than the average since 1979, when satellite records began. This lack of sea ice is causing walruses "to look further afield for places to 'haul out' – pull themselves on to the ice – and this means we are getting more crowding in areas which can have more interference from humans, trampling and frightening, leading to more deaths," Dr Schusterman says. As walruses come ashore earlier, they congregate in extremely large herds, as big as 40,000 in one location last year, and as many as 4,000 are thought to have been killed in stampedes in Arctic Russia.
Professor Georgina Mace, the director of the Centre for Population Biology at Imperial College London and an expert in extinction risk assessment, says that "climate change is causing substantial environmental change for the walrus because of the melting of the sea ice. This is occurring very rapidly and there is concern for all species, including the walrus, that are dependent on the special environments the ice floes form annually." In the 1980s, the walrus population was estimated to be 250,000, but that has dropped to 190,000. "The fear is that a further decrease could occur very rapidly and affect the walrus the same way it has affected other ice-dwelling species, like the polar bear," says Dr Schusterman. Professor Mace laments that: "Change is occurring very rapidly, so rapidly that we could see the total loss of the walruses', and many other arctic mammals', habitat, and a resulting decline in their population."
In February, American scientists called for the Pacific walrus to be added to the list of species considered threatened under the US Endangered Species Act, but the news is not all doom and gloom for the beleaguered walrus. There may be some cause for optimism, according to Erik Born, a biologist at the Greenland Institute of Natural Resources. "There is a theory that looks at the evolutionary history of the walrus and its adaptation and behaviour. I think that it shows the Atlantic walrus will adapt to its changing environment with no great trouble," he says. "They are able to haul out on to land and are physically adapted to use an inflatable pouch to keep them buoyant so will be able to cope." We can only hope that should global temperatures rise, walruses prove to be as adaptable as they are loveable.
On thin ice: arctic animals endangered by climate change
Beluga whale
Notable for its white skin and melon-shaped head, the beluga whale gathers in river estuaries, where it can be affected by human pollution. Poisoning of the St Lawrence river in Canada resulted in numerous incidents of whales with cancer – in fact, carcasses of belugas were so contaminated, they had to be treated as toxic waste.
Polar bear
The polar bear has become a potent image of climate change, and a recent study has shown that the bears are becoming thinner, with lower reproductive rates. It's thought that because Arctic ice is melting two weeks earlier each July than it was 20 years ago, the bears do not have enough time to pack on the fat to get through the winter.
Wolverine
The wolverine has had little contact with man, though its fur has long caused it to be at risk from hunters. In 2008, the US Fish and Wildlife Service determined that the wolverine was "not eligible for protection", despite a decline in wolverine populations, possibly caused by loss of habitat.
Arctic fox
Relentlessly hunted for its white fur and meat, the Arctic fox is reliant on large predators, such as the threatened polar bear, to leave carcasses. It is considered to be one of the most threatened mammals in the European Union.
Narwhal whale
The rarely seen narwhal whale, distinguished by a 3m unicorn-like tusk, was found in a 2008 study to be the most potentially vulnerable of all Arctic marine animals thanks to the effects of climate change.
