Researchers have long known that sea gulls in Argentina attack whales, stripping their skin away and eating their flesh, but they have now uncovered that the assaults are becoming far more common, and are changing the cetaceans’ behavior.
According to IFLScience, scientists working with southern right whales off Argentina discovered in 1972 that gulls were flaying the animals alive, attacking them when they came up for air. When the whales surface, the gulls land, strip off the cetaceans’ skin, and began feeding on the blubber underneath.
— CetaceansAzores (@Whales_Azores) December 2, 2014
As many as eight kelp gulls can target an unfortunate whale in a single attack, and while these assaults were rare when first discovered, they have become far more widespread in recent years. According to Ana Fazio from CONICET, 77 percent of whales in the region displayed scars from gull attacks in 2008.
“Nowadays, gull attacks are so widespread in waters surrounding Península Valdés that it seems that there is no place without this interaction,” she noted.
The wounds aren’t fatal to the whales, but they can be up to 10 cm deep and a meter and a half long. Researchers have recently uncovered that whales are developing new behaviors to combat these attacks. As National Geographic reports, Fazio’s team observed as early as 2009 that the whales were breathing in a defensive manner.
stellwagen bank: gull escapes whale pic.twitter.com/ePDHOQBgJL
— Philip Hoare (@philipwhale) May 23, 2014
Instead of exposing their backs to the offending gulls, the whales rise at a 45 degree angle, breaking the surface only with their heads, and just up to their blowhole. The whales take shorter and stronger breaths as well, submerging as quickly as possible.
Researchers have named the technique oblique breathing, and it has become increasingly common among whale populations, particularly at a site called El Doradillo, where kelp gulls are common. In 2010, researchers observed just three percent of whales in the area using oblique breathing techniques. By 2013, 70 percent of the cetaceans were breathing defensively, and the behavior had spread to neighboring areas.
Recently, a group of humpback whales were filmed in a feeding frenzy off the coast of California that included gulls and sea lions. As the Inquisitr previously reported, orca whales were also present in the frenzy, which took place in Monterey Bay, though they were not filmed.
Oblique breathing is not without its consequences. Whales are naturally buoyant at the ocean’s surface, making the technique extremely taxing on them, particularly calves. Researchers believe that stress from oblique breathing, in addition to kelp gull attacks, may explain a higher mortality rate among the young whales of Península Valdés.
[Image: Nestor Galina via National Geographic]