By Nick Engelmann
It´s grocery day in Córdoba, Argentina, where I live with my wife and two kids. I slip on my jacket, grab my wallet, keys and step outside our apartment building where I'm greeted with a brilliant blue sky and humanity swirling all about me: A mom with her toddler, a group of teenagers on bikes, an elderly couple on a park bench, a taxi driver whizzing by.
These urban images contrast sharply with the landscape of Antarctica, where, during expedition season, I work as guide, lecturer and biologist with Quark Expeditions, which has been exploring the Polar Regions for three decades.
Adaptation( both physiological and behavioral) has allowed penguins to flourish
in the extremes of the Antarctic . Photo: David Merron
Antarctica is the highest, driest, coldest, windiest and most isolated continent on Earth. An astonishing 99% of the Antarctica is covered in ice and every winter the 7th Continent nearly doubles in area with the outward expanse of sea ice. Darkness prevails in winter, then in the brevity of summer, excessive UV radiation makes sunlight a perilous friend. In addition, the continent is frosted in a two-mile (over three kilometre) thick ice sheet.
Yet, there´s an abundance of life.
The Folly of Humans
Homo sapiens set foot on the frozen continent after hundreds of years of struggle. Upon arrival in Antarctica, these seemingly foolhardy travelers—who suffered the afflictions of frostbite, exposure and malnutrition—encountered a world of creatures who seemed to live in relative ease in their icy home.
How could humans be so poorly suited to this environment while creatures as unassuming and comical as the penguin could waddle along with indifference?
One word: adaptation.
Adapt or Die
Adaptation is the dynamic evolutionary process that matches organisms to their environment. This active process gives rise to adaptive traits through natural selection.
Adaptations come in two main forms, physiological and behavioral, and any organism will display a combination of both aspects. A fit and fat penguin won´t last long unless its behaviors are adaptive, as well. Because of the extreme nature of Antarctica, only species with the most refined adaptations have survived here.
Perhaps no creature is more emblematic of Antarctica than the Emperor penguin. In the midst of the harshest of winters, droves of males are busy incubating eggs. Reflect on the fact that in the rest of the world, in temperate climates, like yours perhaps, birds nest and raise young in spring and summer.
The warm, fluffy down is evident on these Emperor penguin chicks on Snow Hill Island. These chicks
will develop outer contour feathers as they grow into adulthood . Photo: David Merron
Emperor penguins rely on two main physical elements to insulate from the outer world: feathers and fat. When winter air temperatures drop to -40°and winds whip up to 100 km/h (60 mp/h), a penguin's internal temperature maintains a cozy 37°C (98.6°F). The Emperor´s feather covering is made of a wonderful variety of feathers including contour and down feathers. Contour feathers form a thick, impenetrable and waterproof cover over insulative down feathers.
Fur, feathers and the wonders of blubber!
Similarly, the Antarctic fur seal, with its thick fur covering, has two main types of hair: guard hairs and underfur. The guard hairs, like contour feathers, provide a water and windproof barrier over the softer insulating underfur. Ironically, their luxurious coat once threatened their survival as it was prized by sealers who slaughtered these seals to near extinction.
The guard hair of the Antarctic fur seal provides a water and windproof barrier over the softer, insulating underfur. Photo: Sam Edmonds
Whether feathers or fur, however, they trap air. And air is a marvelous insulator.
While fur and feathers are fantastic insulators, Antarctic penguins, seals and whales have another form of insulation: blubber.
Blubber isn't just fat. Blubber is a unique dynamic subdermal structure made up of a network of collagen fibers and unique cells called adipocytes. Adipocytes store fat. Blubber is especially important in the marine environment as water transmits heat 25 times faster than air.
While blubber is known for its insulative properties, it also gives mammals and birds their hydrodynamic shape, provides buoyancy, and is a source of energy storage when no food is available, among other properties.
In 1877, American zoologist Joel Allen made an interesting observation. He noted that as one travels from the equator toward the South Pole that warm-blooded animals have an increasingly lower surface area to volume ratio, as well as reduced appendage size such as smaller ears, tails, beaks, etc. This is Allen´s rule.
Put simply, a sphere has a lower surface area to volume ratio than a cylinder and thereby less of its outer surface is exposed to the environment. This is evident among seal species. The Hawaiian monk seal is a tropical seal that's relatively slim and lithe. In Antarctica, the Weddell seal is the opposite. Its neck is barely distinguishable and its flippers are disproportionately small for the size of the animal. In the heat of the Hawaiian sun, monk seals need to dissipate heat and they do that over their large surface. Conversely, Weddell seals need to conserve precious warmth.
The flippers of this Weddell seal are disproportionately small considering the animal's size, but those tiny flippers are key to
conserving precious warmth in the extremely cold Antarctic environment. Photo: Sam Edmonds
Physiological Adaptations of Flippers and feet
While the bodies of penguins, whales and seals are covered in blubber, their flippers and feet remain exposed. When you see a penguin for the first time you might be shocked to see its naked featherless feet. Where the flippers or feet join the body, veins and arteries are intertwined in a unique assemblage called a countercurrent heat exchange. Outgoing arteries come into contact with incoming veins, so that outgoing and incoming blood come in close contact, resulting in a heat transfer from the arteries to veins that prevents a loss of heat to the outside. In addition, marine mammals and penguins can constrict or dilate blood vessels to their exposed limbs to either conserve heat or cool off.
The featherless feet of this Gentoo penguin allows for the necessary transfer of heat and cold. Photo: Sam Edmonds
Guide and biologist Nick Engelmann, on a Zodiac excursion with Quark Expeditions. and guests observe the exposed pectoral fins of a Humpback whale. Photo: Sam Edmonds
While fancy physiological adaptations such as feathers, blubber and a countercurrent heat exchange are indispensable, Antarctic species like penguins wouldn't survive extreme conditions without accompanying behavioral adaptations.
Male Penguins in their Huddles: A Study in Community Parenting
As I write this during North American summer, male Emperor penguins are sitting out the frigid Antarctic winter incubating their eggs, having adopted a particular behavior to ensure survival. In each colony the males form large units called huddles, with about 10 birds per square metre (10 square feet). Using time-lapse photography, researchers have captured the true nature of this phenomenon which almost becomes a unified organism in itself.
Every 30 to 60 seconds there is a shift, a wave of movement, which over time leads to each bird enjoying an amount of equal time both outside (where it's cooler) and inside the huddle (where ambient temperatures can be as high as 37.5°C / 99.5°F ). So effective is this behavior—combined with their physiological adaptations—that researchers have found that penguins in the center of the huddle actually get too warm and shift toward the fringes to cool off. Unusual among penguins, Emperors have actually given up their inherent territoriality. While Gentoos, Chinstraps and Adélies each sit on carefully space nests and barely tolerate one another's company, Emperors have put aside their differences and need for personal space in order to survive.
Emperor penguins gather in a "huddle" to withstand the rigors of the Antarctic climate. Photo: David Merron
Whales on the Move
For other species, however, waiting out the winter isn´t desirable. Baleen whales, such as humpbacks, move. Every year humpbacks in both hemispheres migrate between warm breeding areas in the tropics to cold rich feeding areas. The distance between the breeding areas of Western South America and the Antarctic peninsula is about 8,000 km (5,000 miles) each way.
Around Antarctica there are about seven main feeding areas, each associated with a breeding area further north. In the brief summer, humpbacks gorge daily on tons of high energy krill (tiny crustaceans), replenishing blubber layers that they will use to keep warm and provide the energy to return north, give birth and breed. Keep in mind that once they've left Antarctica there is little or no feeding until the following summer.
Humpback whales have adapted to survive—and thrive—in the cold waters of the Antarctic. Photo: Sam Edmonds
The Adaptive Skills of Humans
Over the course of human evolution, we have adapted physiologically and behaviorally—just like the above species—to different environments. This is evidenced by the Maasai people of East Africa and the Inuit of the Arctic. Human culture has permitted the exchange of ideas and expansion of information which has only enhanced the tools, otherwise known as technology, that allow us to transform environments to suit our physiological needs. Today, humans permanently occupy the South Pole and in the future we´ll be sending settlers to colonize Mars. But we have another adaptation, that perhaps eclipses them all.
Researchers entertain the possibility that humans arose in a time of great climate flux. Our genetic code was written when the earth was unstable, thereby leading to a flexible and adaptable animal.
Adaptability as an adaptation.