Penguin in Peril

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An acute sensitivity to sound may be a defense penguins employ in the face of predators like orcas and leopard seals. One study showed even when asleep, king penguins could distinguish between predatory sounds and harmless sounds. In the presence of an orca call penguins flee upon awakening. Similar to migratory birds, penguins may rest only one half of their brain while the other stays vigilant, constantly monitoring the surroundings for possible threats.

An image of the cover of the Mr. Poppin's Penguins novel. (Little, Brown Young Readers Publishing ) A penguin’s feathers serve to regulate body temperature, increase aerodynamic efficiency underwater, and defend against the elements. Beyond providing insulation, feathers can also minimize drag by trapping bubbles against their body and then releasing them during a dive. A diving penguin emits a visible trail of bubbles as it moves through the water. Penguins take great care of their feathers, often preening three hours a day. An oil secreting gland, the uropygial gland, lies at the base of a penguin’s tail and dispenses water-repelling and microbial deterring oil that a penguin then physically spreads over its body. An artist’s portrayal of Kumimanu coming ashore on an ancient New Zealand beach. Surrounding it are smaller Petradyptes penguins that lived at the same time. This artwork accompanied a study published in the Journal of Paleontology. Yellow-Eyed ( Megadyptes antipodes)- Yellow-eyed penguins are the most private of all penguins, preferring to nest out of sight from other penguins. They often forgo parental duties if they are within eyesight of other nesting couples. For this reason they often nest among the tree trunks of the dwarf rata forests on the islands off of New Zealand where they are native. The breeding season is particularly long, lasting from August to February. Egg incubation alone can take up to two months. They weigh between 5 and 5.5 pounds (2.3-2.5 kg) and reach heights of 65 cm (25 inches). Penguins need to see clearly both on land and underwater. Terrestrial animals, including humans, rely on the cornea—the clear outer layer of the eye—to focus images using a property called refraction, a bending of light as it crosses through different materials. As light travels through the air and enters the eye, it bends to the appropriate angle and creates a focused image on the retina. Underwater, terrestrial animals become far-sighted because the fluid of the eye and the water are too similar, so the light doesn’t bend enough and the image doesn’t focus effectively. Penguins solve this problem with a flattened cornea and highly modified lens. Their flattened corneas have less refractive power than those of terrestrial animals, enabling them to see clearly underwater. Their spherical lenses can compensate for the flatter cornea by also bending the light.

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King penguins are the second-largest penguin species (after emperor penguins), measuring up to one metre tall. But kings are more eye-catching, with vivid markings reminiscent of a tropical sunset. Although feathers can be fluffed up or flattened down, penguins also use other methods to keep their temperatures at the right level. When an Adélie penguin overheats it diverts blood to its thin wings, causing the white undersides to turn a faint pink color. When cold, penguins rely on countercurrent exchange to warm up, a specific heat transferring mechanism that exchanges heat from warm blood traveling in vessels towards their legs and feet to colder blood leaving the area. Senses Feather color is another indicator of male health. Birds in general display the health of their immune systems in what is called an honest signal. Color for feathers is costly since the yellow orange pigments, carotenoids, are also used within the immune system to fight infection. Bright plumage means a healthy bird. However, historically this principle was found in sexually dimorphic birds, where males and females are physically different. Penguins are monomorphic, it’s even difficult for experts to tell the sexes apart. Even so, experiments where king penguin plumage was altered showed that the altered feather colors significantly reduced the ability of males to pair with a mate but not females. Like all penguins, macaronies spend the majority of their life at sea, but when they come ashore, they engage in spirited courtship with coordinated head bops and preening. Male macaroni penguins are stay-at- home dads, taking care of most of the parental responsibilities. The endearing and charismatic portrayal of penguins permeates through mainstream media—in books, movies, comic strips and video games.

The movie Oddball features a little penguin and its canine protectors, based on the Maremma dogs of Middle Island. Macaroni ( Eudyptes chrysolophus)- Macaroni penguins are the most abundant of all the penguins. The most southerly distributed crested penguin, they live along the coasts of sub-Antarctic islands and the Antarctic Peninsula. The lifespan of a Macaroni penguin spans from 8 to 15 years. Macaroni prefer krill but will also eat small fish and squid. They are roughly 27.5 inches (70 cm) in height and between 8 to 14 pounds (3.7-6.4 kg) in weight. Adélie ( Pygoscelis adeliae)- The Adélie penguin is one of two penguins to nest exclusively on Antarctic shores, the only other penguin to do so is the formidable emperor penguin. An ice-dependent species, they rely on the ice for foraging, often trapping prey under ice floes (sheets of ice that jigsaw the ocean surface) and resting on top of them to avoid predators. Populations are on the decline on the northern Antarctic Peninsula, where air temperatures significantly increased in the latter half of the 20th century due to climate change. Breeding season begins in October, with eggs hatching after 35 days of incubation. They rely heavily on Antarctic krill but also eat fish, crustaceans, and other krill species. The birds stand at 27 inches (70 cm) and weigh up to 12 pounds (6.5 kg). The king penguin’s eyes are unique even among penguins. When fully constricted the pupil appears as a pin-sized square but in low light conditions it will expand an amazing 300 fold—the greatest change in pupil size of any bird—to increase light reception. This is especially important when king penguins dive to their greatest depths, around 984 feet (300 meters). The contrast in light is equivalent to bright sunlight and starlight. Because maximum foraging depths can be reached in five minutes, there isn’t enough time for the retina to adapt to the changing light. By constricting the pupil to a pinhole in sunlight the retina is pre-exposed to the lower ambient light levels found at maximum dive depths where the pupil then fully expands.

Only a tad bigger than a bowling pin, little penguins (sometimes called fairy penguins) are the smallest penguin species in the world. These petite paddlers make their homes along the coast of southern Australia, with colonies located on Montague Island and Sydney’s Manly Beach in NSW, the St Kilda breakwater in Melbourne, Victoria’s Phillip Island and the aptly-named Penguin Island in WA (among others). Galapagos ( Spheniscus mendiculus)- Galapagos penguins are the most northerly penguins, living along the Galapagos Islands on the equator. These penguins have special adaptations and behaviors that help them deal with the tropical heat. Galapagos penguins actively seek out shade, pant, stand with wings spread, and hunch over on land to shade their feet, an area of heat loss. Galapagos penguin breeding is completely dependent upon the Cromwell Current and they may breed during any month of the year depending upon seasonal climate conditions. When the Cromwell Current fails to upwell and bring colder, nutrient rich water to the surface, penguins delay breeding presumably because of low food availability. The highly variable climate is influenced by the unpredictable El Niño Southern Oscillation (ENSO). Once the penguins are able to breed, egg incubation is roughly 40 days. The Galapagos are the smallest of the banded penguins at 21 inches (53 cm) and weigh up to 5.5 pounds (2.5 kg). King penguins forage for fish at the Antarctic Polar Front – a region rich in tasty lanternfish, the kings’ preferred food. They will dive up to 100 times per day, reaching speeds of 12km/h in pursuit of a meal. King penguins have been observed diving to depths greater than 300m, and in excess of nine minutes. In the Australian realm, macaroni penguins are found on Heard Island and McDonaldIslands. Although macaroni penguins are the most numerous penguin species in the world, their numbers are declining. Scientists aren’t sure exactly why, but climate change may be affecting the abundance and distribution of their favoured prey. Industrial fishing for finfish and krill is another potential factor. Adélie penguin An illustration of two extinct great auks. The great auk was the first bird to be called a penguin, but the bird is in no way related to modern penguins, instead claiming membership in the Alcidae family, same as puffins, other auks, and murres.