Humboldt penguins – pictured here at Stanley Park zoo in Vancouver, Canada – are natives to the Southern Hemisphere, but sometimes stray far from home.
Credit: Dee Boersma
PERTH: A wayward Humboldt penguin found 8,000 km from home probably stowed away on a fishing boat, according to a new study, which argues the phenomenon is widespread.
The verdict helps solve the mystery of how, over the years, roving penguins have managed to traverse the globe, from their native southern climes to the comparatively far-flung regions of the Northern Hemisphere.
In a sequence of events that wouldn't be out of place in a Disney movie, the record-breaking Humboldt penguin eventually found itself caught in a fishing net off the coast of Alaska in 2002 – more than 8,000 km from it's natural habitat.
After taking a photo of this rare haul, local fisherman Guy Demmert set his captive free. It was Demmert's second brush with a stray penguin; he spotted another individual – in the Alaskan waters the previous year.
Rare but consistent
Sightings of penguins north of the equator are rare but consistent, with a handful of records from the last 25 years. Last month the AFP news agency reported that a Magellanic penguin was found more than 5,000 km north of it native habitat in Chile
Biologists had often wondered how the birds – which are non-migratory and found mostly near to Antarctica – have managed to stray so far from home.
To help solve the mystery, marine biologists Dee Boersma and Amy Van Buren of the University of Washington in Seattle, U.S., explored the plausibility of several different scenarios. They publish their findings this month in the Wilson's Journal of Ornithology.
A couple of theories were debunked as part of the team's research. The experts concluded that zoo escapes were unlikely, as institutes typically keep a close eye on their charges, and shipping penguins to the Northern Hemisphere was halted by international regulations in 1972. They also argue that a penguin making a solo trip is improbable – besides the enormous distances involved, warm tropical regions have little suitable food.
Pet a penguin
After investigating various explanations for how the penguin might have made it so far, Boersma and Van Buren came to the conclusion that the birds were being caught and transported on fishing vessels; and potentially kept as pets which are released before fishermen reached their northern destinations.
"People have always tried to move species around, and that's particularly true for penguins because people like them," Boersma said. "They're still regularly kept as pets in villages in Peru and Chile."
Biologist Belinda Cammell, of Murdoch University, in Western Australia, who was not involved in the research, says there is a similar phenomenon in South Africa, where penguins are often kept as companions. She agreed that the fishing boat theory is a very plausible explanation.
"It doesn't surprise me ... for penguins to travel that distance would be exceptionally difficult," said Cammell who studies penguins in Australia. While the odd penguin "on vacation" from Antarctica has been seen in Australian waters, penguins usually remain in familiar territories and surroundings, she said.
"It's an interesting story," commented biologist Andre Chiaradia, a penguin researcher at the Phillip Island Nature Park in Victoria, Australia. He agreed that the penguin's travel by fishing boat was a good explanation, especially given that a lack of food would deter penguins from crossing the Equator.
Humboldts are one of 17 species of penguin, a group of birds found almost exclusively in the Southern Hemisphere.
In the mid-twentieth century, people tried to establish penguin populations in the Northern Hemisphere, particularly in Scandinavia – but within a decade almost all had died, mainly killed by predators such as bears or seals.
