What’s a Woggin?

Penguins have been called many things over the centuries.  Maori named the Yellow-eyed Penguin of New Zealand the Hoiho, which means “noisemaker” in reference to its loud call. Aboriginal Australians named the Little Blue Penguin “gur-roo-mul”.  In Swahili, a penguin might be called “ndege ya nchi za baridi” meaning “big cold country bird”.  This last version gave rise to the scientific name Dege hendeyi for one of South Africa’s four Pliocene fossil penguin species.  Besides having lots of different names, there has been historical confusion over the word “penguin” itself, and it has been applied both to true penguin and to the recently extinct Great Auk in historical accounts.

One name that historians of ornithology seem to have overlooked until recently is “woggin”.  This name appears in many whaler’s writings during the 1700s and 1800s, and is variously spelled wogæn, waggin, wargan, wargin, waugin, wogen, woggin, woging, woglin, or yawgin.  In 2007, Storrs Olson and Judith Lund published a paper cataloging the various records of this name.  It appears to have been applied to penguins and auks, and it is not too surprising that sailors might confuse two types of black and white feathered, flippered, flightless diving birds. Apparently the word fell out of favor by the era of the Civil War and was until now lost to history. By checking the geographical coordinates associated with each use of “woggin” (usually readily available in ship’s records), the authors were able to pinpoint which references applied to Great Auks, which only occurred in the Northern Hemisphere, and which applied to penguins (which live in the Southern Hemisphere, aside from the equatorial Galapagos Penguin).

Why should we care?  Beyond helping us interpret historical records, uncovering the word woggin can help us understand extinct birds. Luckily, no penguins have gone extinct since the whaling era, but the Great Auk was tragically wiped out by humans in the 1840s or 1850s. We know very little about this bird because few ornithologists conducted studies while it was still alive. Most human encounters therefor took place when the auks were on shore nesting in North Atlantic islands.  However, during the rest of the year Great Auks appear to have roamed far and wide in the ocean.  A sailor’s log from the sloop Sandwich reports that on May 10th 1762, “wogæns” were sighted off the outer banks of North Carolina.

Drawing of a woggin from Beane (1905), after a figure from Olson and Lund (2007).

References:

Beane, J. F. 1905. From forecastle to cabin. New York: The Editor Publishing Co.

Olson, S.L. and J.N. Lund. 2007. Whalers and woggins: a new vocabulary for interpreting some early accounts of the great auk and penguins. Archives of Natural History 34: 69-78.

Penguins in Pots

Last post we talked about how most penguins prefer isolated island habitats.  Well, if you have ever visited Cape Town you may have seen plenty of penguins on the mainland, at colonies like Boulders Beach.  Why aren’t land  predators chasing them off? One of the reasons penguins do so well here is people have given them a helping hand by setting up a nearly perfect environment.  At Boulders Beach, there is a plastic penguin colony set up, in the form of dozens of partially buried heavy-duty plastic pots. Each of these houses a penguin – they serve as little penguin bungalows in place of the usual rock and dirt burrows the birds would otherwise seek out.  Fences keep people from bothering the resting penguins and discourage predators – the only other vertebrate I saw hanging out in the nesting area on my visit was a harmless hyrax.

Shifting Sea Levels, Shifting Fortunes

African penguin diversity over time, from Thomas and Ksepka (2013)

As we discussed last post, penguins were very diverse in Africa in the past.  We have two good geological time slices, one from the Miocene and one from the Pliocene.  At both times, there were four different species inhabiting the southern coast.  Today, there is only one.   This raises the question: what happened to all those extinct species? It might seem natural to point the finger at humans, since we have been involved in the extinction of many flightless birds such as the Dodo, Moa, and Great Auk. In this case, the fossil record seems to exonerate us.  By the time the first human settlers arrive in South Africa, all of the extinct species had already vanished and only the modern Black-footed Penguin was hanging around. Archeological sites show no evidence of early humans roasting up big piles of penguins at campsites, suggesting that overhunting had no role in the extinctions.

A more plausible explanation involves sea level change.  Penguins love islands.  This is because the land is actually a dangerous place for penguins.  Predators like stoats, cats, dogs and even large birds pose a big danger, especially to hatchlings and eggs. This is one of the reasons why penguins tend to breed in isolated places, where there are likely to be few land mammals to harass them. Today, it is possible to see Black-footed Penguins nesting in places like Boulders Beach on the coast near Cape Town. However, the majority of the regional population nest on small offshore islands, where they are safer from land predators.

Over the past 12 million years, sea level along the African coast has ramped up and plunged down like a slow-motion roller coaster. During the time the fossil species lived, there were far more islands in the area. This is because higher sea levels swamped the coast, submerging many low-lying areas and turning hilltops into islands.  These areas would have been prime penguin real estate.  As sea level dropped towards the present, the islands would have been reconnected to the mainland, allowing terrestrial predators to invade.  We suspect this could have removed much of the suitable nesting colony areas, resulting in a lower carrying capacity for penguins and the extinction of some species.

Left: Modern day land surface (gray) in the Saldanha region. Right: Land surface modeled during a period when sea level was 90m higher during the Early Pliocene. Data from Roberts et al. (2011).

References:

Roberts, D. L. et al. 2011 Regional and global context of the Late Cenozoic Langebaanweg (LBW) palaeontological site: west coast of South Africa. Earth Sci. Rev. 106, 191 – 214.

More on Africa’s Penguins at Illuminating Fossils

My colleague Dr. Daniel Thomas has posted some behind the scenes information about the South African penguin fossils we recently reported, including a great explanation of how geochemistry can help us determine under what conditions fossils were deposited and altered, and sometimes place them in time and space.

http://illuminatingfossils.wordpress.com/2013/03/29/african-fossil-penguins-behind-the-scenes/

Plenty of Penguins Once Roamed Africa

Evidence is mounting that Africa was once quite the penguin hotspot. Last year, Dr. Daniel Thomas and I published a paper looking at the biogeography of African penguins – that is, deciphering where they came from.  We found evidence that penguins likely made it all the way across the Atlantic Ocean several times, crossing from South America to Africa by riding out the currents of the South Atlantic Gyre. The fossil species we looked at in that study were about 5 million years old. Today, our  second article was released, detailing fossils from older deposits. These fossils come from the Miocene Saldanha Steel locality, which dates to nearly 12 million years in age.  Penguin bones from Saldanha Steel have a sort of rugged appeal.  They are stained a dark orangy-brown color and have been tumbled around with rocks and sand till they are quite worn. This created a bit of a puzzle, requiring some careful comparisons (and a little bit of adhesive) to figure out what each bone represented.

Although only isolated bones have been found so far, it is clear that there were at least four different species in the area around 12 million years ago.  We can tell this based on the size differences of the elements that were found.  Biggest of the Saldanha Steel penguins is a hefty bird that was about the same size as the living King Penguin (the second largest living species) based on the length of its flipper bones.  In fact, the sternum of the animal suggests it may have been a relative of King and Emperor Penguins, but we will need more fossils to be sure. There are two average sized penguins, represented by an assortment of leg and flipper bones and one lower jaw bone. Smallest of the Saldanha Steel penguins was a tiny Little Blue Penguin sized species that would have been only a foot tall in life. We are lucky to have detected the presence of this tiny fellow, because small bird bones are rare at the site. Only a single vertebra (part of the spinal column) was uncovered. Despite being just a small bit of bone, it is an clear match for a penguin. Penguins have special ball and socket style joints in their lower vertebrae that almost no other birds possess. Beyond this, they have lost the pneumatic openings exhibited by the other birds which have this style of vertebrae (cormorants and gannets).

We were surprised to find so many different size classes living in the area. In the next post, we will explore what may have been going on back in the Miocene.

Bones from different sized penguins found at the Saldanha Steel fossil site, with bones of the modern King Penguin, Black-footed Penguin, and Little Blue Penguin for scale.

Reference: Thomas, D.B. and D.T. Ksepka. In Press. A history of shifting fortunes for African penguins. Zoological Journal of the Linnean Society.

First Fossil Penguins from East Antarctica

Some new penguin bones have been discovered on the frozen continent of Antarctica.  It may seem natural to think that most fossil penguins would come from Antarctica, given our fascination with the icy travels of species like the Emperor Penguin. However, there are few places paleontologists can look for fossils on the continent. Very few rocks are exposed for prospecting due to the overlying ice sheets.  Up until now, all of the penguin fossils have come from West Antarctica.  In fact, they have all been from Seymour Island, which is part of the archipelago of islands off the tip of the Antarctic Peninsula. Although these fossils include some amazing species, this geographical restriction has greatly limited our knowledge of the history of the southernmost penguins.  The oldest reported bones are assigned to the species Crossvallia unienwillia from the late Paleocene (about 55 million years ago). We know there was a diverse group of species of all sizes, including some giants, thriving from about 50 million years ago to about 35 million years ago. Most of this  interval in Earth history was quite warm, and the penguins were living in a fairly temperate environment complete with forests.  Over the next 35 million years, climate cooled leading to the growth of ice sheets which eventually covered almost all of Antarctica.

What happened to the penguins?  Did they adapt?  Did they die out? If so, when did new species replace them? Today, several species of penguin breed in Antarctica including the Emperor Penguin, Adélie Penguin, Chinstrap Penguin, Gentoo Penguin, and Macaroni Penguin.  We know that these modern species are distantly related to the original archaic penguin inhabitants of Antarctica.  But, because of the big gap in the fossil record we are not sure when the new species first arrived and what happened in the meantime.

A penguin humerus from the Prince Charles Mountains. Photo courtesy of Dr. Piotr Jadwiszczak of Bialystok University.

The new fossils were discovered at Prince Charles Mountains, which is in East Antarctica, almost directly opposite from the Seymour Island sites.  Two flipper bones, a humerus and a radius, were found in a shell bank.  This was a fortuitous place for the find, because shells can be dated with isotope methods. The scientists looked at the levels of a radioactive isotope of the element Strontium to figure out the age of a scallop found near the penguin bones.  These tests indicate the fossils are 10.2 million years old, much younger than the previous fossil records from Seymour Island.

Features of the bones suggest they belong to the genus Spheniscus, the group of “tuxedo penguins”.  That’s an interesting fact, because today Spheniscus penguins (including Galapagos and Black-footed Penguins) are some of the species most adapted to warm conditions.  They make it south as far as Tierra del Fuego, but don’t cross over to Antarctica.  Because things are already quite chilly in the south by 10 million years ago, it is a surprise to see a Spheniscus penguin in the region. I am very excited by the first announcement of bones, and hope more is in store. East Antarctica may well hold some important secrets of penguin evolution.

Reference:

Jadwiszczak P., Krajewski K.P., Pushina Z., Tatur A. Zieliński G. 2012. The first record of fossil penguins from East Antarctica. Antarctic Science, FirstView Article, pp 1-12, DOI: http://dx.doi.org/10.1017/S0954102012000909; Published online: 15 November 2012.

Penguins on the Prowl

Critter cams are revealing the efficiency of Adélie penguins in picking off prey.  A recent study by Dr. Yuuki Watanabe and Dr. Akinori Takahashi involved attaching small cameras and speed monitors to penguins in order to see firsthand how they forage.  The penguins turned out to be remarkably skilled hunters, gathering prey with unerring accuracy and breathtaking speed.  In dense prey swarms, they can capture two krill per second.  One bird gobbled up over 200  krill in about an hour. And it turned out that they can be sneaky, using the ice as a barrier to trap fish. It is impressive to see how rapidly the penguins move their heads, and it makes me think about their brain structure.

Reference: Watanabe, Y. and A.Takahashi. In Press 2013. Linking animal-borne video to accelerometers reveals prey capture variability. Proceedings of the National Academy of Sciences.