Dead Penguins Found Closer to Equator Than Ever Before
Sabrina Valle in Rio de Janeiro
for National Geographic News
|August 5, 2008|
With hundreds of dead or sick Magellanic penguins washing up along the Brazilian coast in recent weeks, experts are struggling to figure out why so many have been appearing—and why they're so much farther north than usual.
In July and August—winter in South America—it is common for a few dozen young penguins to wash up as far north as Rio de Janeiro state.
That's because each year thousands of the animals living in Patagonia, at the southern tip of South America, swim out to sea in search of fish and get swept up in strong ocean currents that carry them northward.
A few casualties along the way are inevitable, especially among younger birds that are not strong enough to survive pollution, disease, or other incidents.
But this year wildlife officials say they have found about 500 dead or dying birds along the coast of the northeastern state of Bahia—much closer to the Equator than the penguins have ever been found before.
"Global warming is the logical cause," said climatologist Jose Marengo of Brazil's National Institute for Space Research (INPE) and a member of the UN's Intergovernmental Panel on Climate Change.
"Sea currents are a reflection of wind patterns. This winter has started earlier and, so far, has been more severe," Marengo said.
As a consequence, the ocean currents in which the penguins travel can get stronger on particularly cold days, taking the birds farther north.
Still, the South Atlantic is one of the "big holes in climate knowledge" in the Americas, Marengo cautioned. There are no historical statistics that could prove global warming is affecting local sea currents.
Sick and Tired
As of July 30, workers in Bahia were treating 474 sick penguins, said Sheila Serra, a biologist at the Sea Mammals Institute in the state capital of Salvador. In addition, more than a hundred penguins had been found dead in Bahia.
Last year the institute saw no injured penguins at all, Serra noted. The most they had ever seen until recently was 20 in 2001.
This year penguins "started arriving on July 17, and now we are getting dozens of calls a day. We don't even have places for them all, nor time to count all the deaths," she said.
For the birds in Bahia, the most likely cause of death was sheer exhaustion, Serra said. After swimming for thousands of miles, the penguins arrive weak and anemic, often with severe weight loss.
Meanwhile, about 750 miles (1,200 kilometers) southwest, more than 400 penguins have been reported dead along Rio de Janeiro's beaches. (See a map of Brazil.)
In addition to weariness, many of these seabirds appear to be suffering from pollution-related illnesses.
Andre Lima of Niteroi Zoo in the city of Rio de Janeiro said that, while only eight penguins were brought into the zoo for treatment last year, this season more than a hundred have arrived.
"Lots of them show up with oil stains" Lima said. "Others are sick from sea pollution or have [fish] bones in their mouths" from species that are much larger than ones the penguins usually eat.
The birds soaked in oil are the most vulnerable, noted Gilberto Manzoni of the Mammals and Seabirds Lab at the Universidade do Vale do Itajaí.
(Related: "Oil-Slicked Penguins Wash Ashore Dead in Argentina" [May 12, 2006].)
"The oil deregulates the mechanism that controls their body temperature," Manzoni said.
"They leave the water to get warm, using up a lot of their energy and so losing their capability to search for food."
Some of these birds fall victim to misinformed beachgoers, who try to rescue the penguins by taking them home and putting them inside the refrigerator or in buckets of ice. Many of these animals, already weak, end up dying.
Sick penguins that are instead taken to zoos or other institutions can improve after weeks of medical care.
The Brazilian government usually flies survivors to the south of the country, where the penguins can catch currents back home.
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