Photo credit: Christopher Michel
-Emperor penguin scientific name is Aptenodytes forsteri. “Aptenodytes” in Greek means “without wings diver” and “forsteri” comes from J.R. Forster, a naturalist and colleague of Captain Cook who was one of first to describe penguins in the 18th century.
-Emperor penguins are endemic to Antarctica. They can almost exclusively be found between the 66° and 77° south latitudes.
-In 2009, biologists estimated that there were around 595,000 adult emperor penguins.
-In 2012, the emperor penguin was uplisted from a species of least concern to near threatened.
The primary causes for an increased risk of species endangerment are a loss of habitat and a decline of food availability due to global warming.
-Emperor penguin males and females are similar in plumage and size and therefore hard to distinguish.
Their tuxedo-like black and white colouration is thought to be particularly important for camouflaging from predators and prey whilst in the ocean. Indeed, if a predator swims below a penguin, the penguin’s white belly blends in with the bright sunlight coming from above. Likewise, if a penguin swims below some fish it wants to catch, its black back blends in with the dark depths of the sea.
Emperor penguins are the largest of penguin species with an average height of 1.15 metres (3.8 feet) and an average weight of around 30 kilos (66 pounds), with males being heavier than females.
-In order to survive in such hostile conditions, emperor penguins have 4 layer of dense, oily and waterproof feathers and a thick layer of blubber under their skin.
The feathers are highly specialised and modified compared to the feathers of flying birds: they are smaller, stiff, lanceolate and more packed.
-Each emperor penguin has a unique and distinctive call that allows them to find their partner and chick.
-The life span of emperor penguins in the wild is typically 20 years. But observations suggest that some individuals may reach an age of 50 years.
However, only 19% of chicks survive their first year of life. Therefore, 80% of the emperor penguin population comprises adults five years and older.
-Emperor penguins are very sociable and live in colony. They conduct almost very aspects of their daily lives together. Among other, it allows them to stay safe and warm.
-As a defence against the cold, a colony of emperor penguins forms a compact huddle (also known as the turtle formation) ranging in size from 10 to several hundred, with each penguin leaning forward on a neighbour. Once a penguin has warmed a bit, it will move to the perimeter of the group so that others can enjoy protection from the icy elements. All the juveniles usually stay in the center. It’s a very unusual behaviour for adults of other penguin species which are usually aggressively territorial.
-Emperor penguins can’t fly. From a morphological point of view, they have wings but from a functional point of view they are
-Emperor penguins can walk, swim and toboggan.
They walk slowly and don’t hop, with a maximum walking speed of 2.8 km/h (1.7mph).
They have an average swimming speed of 6–9 km/h (4–6 mph).
They are also known to toboggan: sliding across ice on their bellies.
-Emperor penguins are carnivore. Their diet consist primarily of fish, krills, squids and crustaceans.
An adult penguin eats 2–3 kg per day. But when they need to fatten up before a moult or at the start of the breeding season, they can eat as much as 6 kg per day.
-Emperor penguins don’t have teeth but hundreds of spines on the roof of their beaks.
-Emperor penguins can’t breathe underwater. However, they can dive down to 565 metres (1850 feet) and remain there for around 20 minute when hunting. This is possible thanks to their abilities to shut down non-essential organ functions, to tolerate a low level of oxygen in their body and to handle the effects of pressure.
-Emperor penguins can drink salt water thanks to a spuraorbital gland that filters all salt intake from its bloodstream.
-Emperor penguins are extremely short-sighted. However, they see equally well in and out of water.
-Emperor penguins are able to breed at around 3 years of age, and usually commence breeding around 1 to 3 years later.
-Emperor penguins are serially monogamous. They have only one mate each year, and stay faithful to that mate. However, fidelity between years is only about 15%, which is the lowest rate of fidelity among penguin species.
-The yearly reproductive cycle begins at the start of the Antarctic winter, in March/April, when all mature emperor penguins travel to colonial nesting areas, often walking 50 to 120 km (31 to 75 miles) inland from the edge of the pack ice. Emperor penguins lay and incubate their eggs during the coldest time of year in the coldest place on Earth. It’s the only penguin species that breed during the Antarctic winter.
-Emperor penguins mate together in large breeding groups called rookeries.
-Emperor penguins have mating rituals. Lone male gives a courtship call for about 2 seconds. Once a female seems to be interested in, they will stand face to face, with one extending its head and neck up and the other mirroring it. The pair will then waddle around the colony, with the female usually following the male. They will then face again and bow to each other before copulation.
-Emperor penguins, like all birds, have internal sexual organs. For both females and males, the sexual organ is called the cloaca. The urogenital opening is where they defecate as well as have sex. It’s just a little hole in their rump area.
When mating, the female will lay on her belly and the male will climb on top in order for both cloacae to be pressed on each other. This is a very difficult process because the male has to balance on the female’s rounded body.
-In May or early June, the female penguin produces one single egg weighting 460–470 g (1 lb), which represents around 1.5% of its mother’s body weight, making one of the smallest eggs relative to the maternal weight in any bird species.
There are no materials to build nests from in Antarctica but the egg has to be kept warm until it hatches. After laying, the male partner immediately takes over the caring duties because the mother’s nutritional reserves are exhausted. She very carefully transfers the egg to the male, before immediately returning to the sea for 2 months to feed.
The transfer of egg can be awkward and difficult, and many couples drop it in the process. When this happens, the chick inside is quickly lost, as the egg can’t withstand the freezing temperatures on the icy ground.
The male keep the egg warm by balancing on its feet and covering it with a special fold of abdominal feathered skin known as a brood pouch. But they don’t sit on the egg, as many other birds do.
-The incubation takes about 65 days. By the time the chick appears, his father will have fasted for 4 months! Most male penguins will lose about 12 kg (26 lb) while they wait for the chick to hatch. They rely entirely on the body fat that they laid down during summer to survive the long winter fast. With an average temperature of around -20°C (-4°F), which can drop down to -50°C (-58°F) and with winds that gust up to 200km/h (124mph), they survive by huddling together for warmth.
-Hatching may take as long as 2 or 3 days to complete, as the shell of the egg is thick to minimize the risks of breakage.
A freshly hatched emperor penguin chick weighs between 120 and 160 g (0.26 to 0.35 lb) and is approximately 15 cm (6 inches) long.
-If the egg hatches before the mother is back, the starving father still finds the ressource to feed it with a substance know as penguin milk and composed of 59% protein and 28% lipid, which is produced by a gland in his esophagus. This feeding allows the young to survive for up to 2 weeks after hatching.
If the father is not relieved by its partner before its own energy reserves are depleted, then it returns to the sea to re-feed, abandoning its doomed egg or chick at the colony site. Abandoned chicks don’t survive.
-If the egg hatches when the mother is back, she will remove the chick from the male and immediately regurgitates food into the beak of the newborn. She finds her mate among the hundreds of fathers by his vocal call.
Sometimes, the father doesn’t want to give up the baby. He eventually does and leaves to take his turn at sea, spending around 24 days before returning.
-The chicks are brooded on the feet of their parents for 50 days before they are able to regulate their own body temperature.
Then, the chicks form a “crèche”, huddling together for warmth and protection. During this time, both parents forage at sea and return periodically to feed their chick.
Each chick needs about 42 kg of food from each parent.
It takes about 150 days to rear an Emperor penguin chick.
-From early November, chicks begin moulting into juvenile plumage, which takes up to 2 months and is often not completed by the time they leave the colony; adults cease feeding them during this time.
-Come December, the warmer temperatures break up the ice that the penguins occupy, bringing open waters closer to the nesting site. When the young penguins reach the water, they are nearly done with their moult, and they’re ready to swim and fish on their own. Adult penguins begin their yearly moult once separated from their offspring. They store up body fat beforehand because it takes a lot of energy to replace all their feathers, and they are unable to fish because they lack waterproof protection. Moulting is rapid in this species compared with other birds, taking only around 34 days. Emperor penguin feathers emerge from the skin after they have grown to a third of their total length, and before old feathers are lost, to help reduce heat loss. New feathers then push out the old ones before finishing their growth. By January, the new plumage has grown in, and the hungry penguins take to the waters in groups to forage for the summer.
Seeing emperor penguins in Antarctica is definitely on my bucket list. I just need to spare as it is a quite expensive travel!
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