Archive for March 2010
Many of us have seen ads where a penguin and polar bear share a bottle of Coke at the North Pole. Of course, we all know this is a crass attempt to use our love of penguins to promote soda. Penguins don’t occur naturally in anywhere in the Northern Hemisphere except for a few hundred yards above the equator at the northernmost part of the Galapagos Islands. Other than this, zoos and aquariums are usually our only chance to encounter these birds without heading South. Usually is a key word, because penguins have actually reached Arctic and near-Arctic waters several times in past century, though it has not always been clear how.
Often, humans are implicated. Perhaps the most serious attempt to stock our Northern oceans with penguins occurred in the 1930s. In 1934, Norway’s Nature Protection Society released 9 King Penguins into the Baltic. Gentoo and Macaroni penguins were also released a few years later. The idea was supposedly to replace the recently extinct Great Auk. At a glance, the Baltic countries might seem like a great place for penguins. It’s cold, there are fish populations similar to those in the Antarctic for prey, and no natural competitor for the flightless diving bird niche. However, the challenges are also great. Unknown predators and disease would have posed an instant danger to penguins that evolved in a different hemisphere. Moreover, the population deck was stacked against the Nordic penguins from the beginning. With few individuals, chance events could easily wipe out the whole group and low genetic diversity may have taken a toll had they made it past the first few generations.
So what happened to these unwilling flippered pioneers? Sadly, all of the Gentoo and Macaroni Penguins were gone in a year. Some seem to have fallen prey to fishing nets, others to native predators. The King Penguins survived much longer. Some even reared chicks successfully, as young birds were sited (and in one case eaten) several times years after the initial release. Hatching eggs successfully must have required “resetting” the breeding cycle, as in the wild King Penguins tune their egg laying and chick rearing to the seasons. They lay their eggs in the Southern Hemisphere Spring (which corresponds to the Northern Hemisphere Fall), incubate them for nearly two months, and tend to the hatchling for nearly a year until it is fully fledged. If the Norwegian penguins tried to lay their eggs at the “normal” time, they would end up hatching in the dead of the Northern Hemisphere winter to disasterous effect. Zoo penguins are usually able to make to switch to the Northern calender though, and its quite common for penguins to breed successfully in outdoor zoos in the US and Europe.
At least one of the released penguins was shot by locals. I’ve heard two different explanations in popular accounts of this incident – one that the shooter found the penguin in molt, thought it was very sick, and put it down to be humane, and the other that the shooter suspected the penguin was a demon. Whichever the true reason (or perhaps these were two separate incidents), it shows a poor understanding of penguin ecology. A molted penguin is indeed usually not very happy, but it will grow its feathers back quickly and isn’t the slightest bit infernal.
On July 18, 2002 a boat fishing off of Noyes Island, Alaska, hauled in a penguin with a net. This fellow turned out to be a Humboldt Penguin, a native of Peru and Chile. The penguin was angry by firsthand accounts, and allegedly took about half an hour to calm down enough that it could be grabbed and tossed back into the sea.
Biologists A.N. Van Buren and P. Dee Boersma wrote an article reviewing this incident and other cases of loose penguins in the Northern Hemisphere. They hypothesize that over evolutionary time, the big barrier keeping penguins restricted to the Southern appears to have been temperature. As the cases above demonstrate, at least some species of penguins can survive and even propagate in the North. But to get there, they need to cross the equator. The waters here are not penguin-friendly, with sea surface temperatures reaching above 30 degrees C. At this heat, penguins have trouble shedding excess body heat because the layers of fat and feathers that protect them in cold water trap too much heat in. Its likely most penguins would not be able to survive even a few days under such conditions. Furthermore, currents may play a role. Its fairly easy for penguins to end up far North of their normal geographical range (often unintentionally) by “riding” the Humboldt current up the west coast of South America. But this free ride stops near the equator. Think back to the Age of Sail, with ships stuck for weeks in the doldrums. This provides an analogy to the penguin stranded in the low tropics, though an imperfect one – the unfortunate bird rather than lacking wind for its sails might instead by drifted off into the open overheated seas as the current veers off coast.
So, how did our newsworthy Alaskan penguin get there? Van Buren and Dee Boersma suggest the animal may have hitched a ride unintentionally on a north-bound boat, or more likely, been picked up for fun by sailors and then later discarded. They even hypothesize this penguin could have been in Alaskan waters for several years, as the same species was spotted around Vancouver Island, Canada in 1978 and near Washington in the 1980s. And since the bird was tossed back, for all we know it is still prowling its new territory right to this very day.
Simpson, G. G. 1976. Penguins Past and Present, Here and There. Yale University Press, New Haven.
Van Buren, A.N. and P. Dee Boersma. 2007. Humboldt Penguins (Spheniscus humboldti) in the Northern Hemisphere. Wilson Journal of Ornithology 119 (2): 284-288.