The Washington Post
Horrific things you might not know about the natural world: In the 1970s, researchers observed that Argentinian kelp gulls had begun to rip at the skin of living whales in order to feed on them.
And in recent years, recorded instances of this gull-on-whale violence have only gone up. By 2008, researchers were seeing gull-inflicted wounds — tears, sometimes nearly 8 inches long and cutting down into blubbery fat, in their backs — on 77 percent of the whales they found. Mother and calf pairs were targeted the most.
The gull populations have increased during that time, Ed Yong writes for National Geographic, and it’s possible that the savaging birds have learned that surfacing whales are easy targets by watching other gulls dive in for snack time.
But according to new observations published in the journal Marine Biology, the whales may be learning new tricks to make their backs less of an all-you-can-eat buffet for the birds.
Usually, when they come up for a breath, they do so in a leisurely way, lying parallel against the water surface with much of their backs exposed. But in 2009, lead author Ana Fazio’s team saw that a few of the whales would instead rise at a 45 degree angle so that only their heads were exposed, and only up to their blowhole. Their breaths were shorter and stronger than usual, and they quickly submerged again.
With this new technique, less of the back is exposed as the whale breathes — and it seems to be most common among whales living in the area where gull attacks are also especially common. The use of the technique, which the researchers have dubbed “oblique breathing,” has increased from 3 percent to 70 percent at that site in just three years, and is spreading to surrounding areas as well.
Unfortunately, it’s an energy-intensive — and counterintuitive — method of breathing, so it may be tough for calves to learn successfully. Local officials are working to cut down on gull populations, which were probably bolstered by the use of open landfills, but calves in the region are still suffering unusually high mortality rates — so the battle against the birds is far from over.