Pinguini ●Pinguin● Pinguoin ● Pingvine ● Pinguine ● Pinguino ● Pingviner ● Pingwiny ● Penguin
No matter what the language, penguins are among the most recognizable birds on the planet. Penguins enjoy a constant familiarity although they reside in the Southern Seas. Zoos and aquaria across the world bring these animals to the general public with giant viewing windows above and below the water. From that lookout, you can see the aquatic birds flying through the water like missiles. Their black back and white front gives the impression that they are naturally over-dressed in a tuxedo. Beneath the water, penguins soar, swim and dive, but with their wings by their side, they could never take flight. They boast a short stature and waddle with clumsy movement which is easy to imitate. Popular culture depicts them as animated characters in cartoons, movies, mascots and product advertisements. Holiday merchandise portrays happy penguins alongside North Pole residents: Santa Claus and polar bears. For real penguin enthusiasts, expensive tourism journeys bring humans to the land of the penguins close to the South Pole. “If more people watch penguins in captivity than in the wild, what do we really think of these birds?” (Strycker 44)
But why do they captivate us so? One simple answer to penguins’ worldwide popularity is that they seem so cuddly. An unassuming image search results in countless pictures of baby chicks covered with fluffy down feathers. Yearly baby animal calendars always have the penguins as the winter display model. Stuffed animals have smiling beaks and eyelashes sewn onto the face. Even though they seem so delicate, they mostly inhabit a continent of ice with a seemingly unrelenting winter. Another reason for their endearment to humans could be that they have become the model organism for the South Pole. “The best word to describe the life of penguins in the Southern Hemisphere is ‘harsh’. Some of the most extreme conditions on earth have forced them to adopt highly specialized forms of behaviour to adapt to the weather and terrain” (Rouse and Rich 22). Movies and books have anthropomorphized penguins with human characteristics and traits, and have attributed these human features to their survival against all odds. One trait includes dedication as the male and female risk their lives, starvation and future by jointly sharing the burden of caring for an egg, then a chick. Witnessing this balance of life raises both awareness and concern for the penguin species. “Penguins have thrived in the oceans of the Southern Hemisphere for millions of years but they have encountered many threats to their survival since their discovery by man” (deNapoli 41). Penguin biology, ecology and global threats will be discussed here while their role in pop-culture and resulting conservation efforts is recognized.
No entomological origin for the word “penguin” has been identified. Some suspect that the Welsh form of ‘pen gwyn’ meaning “white head” first named the
Great Auk, while others presume a Latin origin of ‘pinguis’ named for bird blubber (Stryker 42).
Currently, eighteen species of penguins are recognized. Their body sizes differ dramatically among the species; the largest being The Emperor Penguin tops off at 41kg, and the aptly named Little Penguin weighs 0.5-1.1 kg (Shirihai 43). The various species can live anywhere from 10-50 years. Both genders of a species have identical coloring. However, cheek or eyebrow plumage colors vary between the groups and can be yellow, orange, and pink or speckled (British Antarctic Survey 1). Unlike other birds, the male is larger than the female and has matching feathers. Besides the inability to take flight, penguins differ from other birds via the construction of their bones. A penguin skeleton actually has bone marrow which makes them incredibly dense (similar to mammal bones), and allows for deep oceanic dives with minimal effort controlling buoyancy.
Evolution helped penguins overcome the impediment of this increased friction in several different ways. To reduce drag in the water, their bodies developed a streamlined football shape, and both their wing and their feathers became much shorter and stiffer than those of their flighted relatives. Their flat wings, which are slightly tapered from front to back like an airplane wing, are powered by massive chest muscles; and where flighted birds only get forward momentum on the down stroke of their wings, penguins move forward on both the down stroke and the up stroke by changing the pitch of their wings…And though penguins have webbed feet, theirs is not used for propulsion as with other aquatic birds, so you will never see them paddling like a duck. Instead, their feet are solely used for steering-and occasionally for reducing speed. As it swims, penguin lets both feet trail straight out behind it, with the bottom surface of the feet facing toward the sky. When it wants to change direction, it dips down one foot, pointing its toes… (deNapoli 34-35).
Unlike most aquatic birds, penguins can actually consume sea water and do not need freshwater. “Salt glands, located under the skin above their eyes, process and excrete the excess salt in their systems, allowing them to drink salty ocean water…Penguins also get the hydration they need from the food they eat” (deNapoli 36).
Since the female chooses the mate, they remain monogamous during one season. However, not all penguins mate yearly. Typically, females deliver one and sometimes two eggs in a reproductive season. “[Penguins] must live divided between the ocean, which feeds them, and the ice, which is a barren but safe desert, a true oasis for their chicks” (Jacquet 11). They court in autumn, copulate and then birth the egg in winter. During incubation, the egg rests on top of the clawed feet beneath a fold of blubber-enriched flesh. Especially in the Antarctic, an egg must be protected by all costs from the freezing winter. One novel way to achieve this is to huddle in close proximity. Huddling alone can raise temperatures 10ºC within the group, and protect from wind gusts (Jarman 62). Both parents contribute to watching the egg, preventing it from freezing, and monitoring the hatching stage. In captivity, two male chinstrap penguins exhibited the rituals for chick-rearing and incubated a rock for the season (Driscoll 1998). Even though this behavior has rarely been documented, more research is needed. Penguins do not produce milk from mammary glands, so they have developed a way to regurgitate their krill, squid and fish diet into the young’s beak. These small meals sustain the fledgling. Spring and summer is just enough time for the chick to learn basic survival skills such as swimming, avoiding predators and molting their fluffy, grey, juvenile feathers for the rigid scale-like adult feathers (Watson 63).
The parents rotate feasting and chick-sitting in shifts so the chick is not left alone. As the chicks become more independent, they start huddling in small groups called crèches (Watson 63). This ‘safety in numbers’ theory reduces the risk of predation by skuas, gulls, and petrels. Surprisingly, the penguins, Order Sphenisciformes, showed no adolescent or post-fledgling care by parents (Polito and Trivelpiece 231). Most chicks and fledglings remain on or near their birthing colonies. Scientists have remarked that these aquatic birds have a homing device to remember the geography of their natal habitats. Some adolescent penguins make a deadly mistake of following schools of fish through migratory patterns. A temporary surplus of fish confuses the fledglings by leading them further out to sea or to unfamiliar shorelines. This sends them way off course away from their natal beaches which could lead to vagrant numbers in locales in which they do not belong “51% of the stranded penguins were emaciated or dehydrated when captured, indicating a lack of food,” (Wilkinson et al 111). Particular penguin biological and ecological adaptations aid in their continued existence.
How exactly do penguins survive year after year in the frigid southern latitudes? Their specialized body is structured to wane off heat, or conserve it when needed most:
Penguin physiology is highly specialized in order to withstand the very low land and sea temperatures that most species endure for much of the year; various insulative, circulatory, metabolic, and behavioural adaptations have evolved for this purpose. The feet and, in some species, parts of the facial region are unfeathered, the undersides of the flippers which are sparsely feathered, and all are served by an abundant blood supply near the surface in order to dissipate heat during high temperatures or periods of exercise when diving. Penguin feathers are unusual in being very stiff, relatively short and packed very densely over the entire body, which traps warm air next to the skin and waterproofs the body. Antarctic and subantarctic species are further insulated by dense subdermal fat. (Shirihai 42)
For each yearly adult molt, all feathers are replaced. They stay out of the water for up to four weeks as new feathers are replenished. This leaves the penguins vulnerable to predators, and reduces the water-proofing. Penguins have a higher quantity of feathers than any other bird, which could explain the extensive molting time (deNapoli 37).
When penguins dive and forage for food, they face an unpredictable availability of foodstuff. They have adapted and can change their diet. Summer and winter food consumption differ because of obtainability (Kirkwood and Robertson 155). While they do prefer krill to fish, squid is an acceptable substitute (Kirkwood and Robertson 167), a penguin’s diet is dependent on what is accessible at that dive. A few scientists predicted that some species could spend up to 75% of their time swimming, foraging and diving for food (British Antarctic Survey 2).
Most penguins are never witnessed by humans swimming underwater in nature. So how do ornithologists obtain data? First, they can use
flipper bands (Parmalee 27). Or they can glue a
TDR or time-depth-recording device to a penguin (Putz et al. 127 and Sims et al. 1101). In some cases, they are solar-powered or battery-run and either fall off naturally or stop working. The final option is the state-of- the-art satellite tags with real-time data transmission and built in GPS (Strycker 163). Land surveys are easier to complete by performing head counts, egg counts, nest counts, aerial photography, or chick weigh-ins each season. These ecological monitoring tools have aided scientists in understanding population changes over decades. As with any scientific observation method, the limiting of human interaction and therefore disturbance is critical for objective results and further harm to populations (Wienecke 164).
Considering their shared time between land and sea, community ecology in the coastal ecosystem is an important study topic. The
trophic pyramids of oceans are never quite as obvious as they seem. But with isotopic analysis of
δ15N in food webs, plant and animal tissues, and shells/bones a clear hierarchy of organisms exist. Each trophic pyramid begins with the producers, then herbivores, next are consumers, and secondary consumers. Penguins that regularly consume krill (an herbivore), fish, and squid find themselves high in the food chain (Dunton 105). Since penguins are food sources themselves, they contribute to other seabird, seal, and orca diets. Exact ratios of carbon and nitrogen assimilation can be traced. By observing the predator/prey relationships, penguin populations are naturally prevented from over-population. Future research will be investigating further foraging decisions made by penguins if food sources are depleted. By knowing life history strategies and recruitment rates for all penguin species, colony size can be accurately judged as declining, increasing, or having no change (Hinke 851-853). Population sizes are compared among all penguin habitats.
“Most Penguin species and their numbers or biomass occur on oceanic islands outside of Antarctica, in a more hospitable zone called the Sub-Antarctic. Many also reside on the other three southern continents whose waters abut the great Southern Ocean” (Parmalee XV). The geographic area naturally for penguins is below the equator all the way to the South Pole on Antarctica. In common habitats, groups of penguins in a geographic area used to be called rookeries, but now retain the name colonies. Land and sea in the Southern ocean, near the Atlantic, Indian and Pacific oceans, house the great penguins of the world.
Table One: List of all eighteen penguin species with their geographic locations and conservation status. Data compiled from IUCN 2012. The range of the Subantarctic zone extends to 55°S latitude.
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