Introduction : Difference between penguins and auks 2
Origin and evolution 3
The different species of penguins 3
First group (Aptenodytes) : the great penguins 4
The King Penguin 4
Second group : crested penguins (Eudyptes) 4
Macaroni penguin 5
The 3rd group : the northern penguins (2 family - Spheniscus) 5
The magellanic penguin. 5
The last group : the brush-tailed penguins (pygoscelis) 6
Chinstrap Penguin, also called Bearded penguin. 6
Gentoo Penguin 6
Penguin : shapeless birds ? 7
So penguins became excellent swimmers 8
Penguins also had to adapt themselves to cold 9
1st: feathers. 9
2nd: color 9
3rd: fat 9
4th and possibly: body temperature 9
So penguins became also very good walkers 9
An advanced social organization 10
Uncertain nesting 10
Both parents contribute to education 10
An ocean of food 11
Penguins are prey too ! 11
Last threat: Humans 12
Introduction : Difference between penguins and auks
Just as the polar bear is the symbol of the Arctic regions, penguins represent the emblem of the Antarctic. And it’s justified, because it’s a very special animal, extraordinary well adapted to one of the most extreme world climate.
And we are talking about penguins and not auks, even if we usually mix them up. Why this confusion?
First, because they look very much the same:
same black color on the back and white on the belly
same capacity to swim under water,
same climatologic conditions. They even have the same flightless cousin, the Great Auk (extinct since the 19th century). The first naturalists who saw penguins believed they were auks.
But of course they soon realized their mistake and it became evident that they belong to two complete different families. In fact, it’s their evolution or the adaptation to their environment which is very similar.
So in fact there are 2 families:
on one hand the Alcidae, called auks,
on the other, the Sphenicidae, called penguins.
The Alcidae (puffin, guillemot, little auk,…) :
live only in the northern hemisphere,
have the ability to fly (except the Great Penguin which was flightless, but as it has disappeared, there’s no more possible confusion) - the use of the wings allows them to nest and breed at the top of cliffs, secured from terrestrial predators like foxes or ermine.
they’re globally quite small : the smallest weighs 150g to 1 kg for the larger ones.
The Sphenicidae :
live only in the southern hemisphere (except Galapagos penguin which live at the Equatorial latitude)
are incapable of flying
are much bigger : the smallest weighs 1 kg (little penguin) up to 45 kg for the Emperor.
If penguins are that big, it’s to improve resistance to the cold conditions. Indeed, the bigger the animals are, the more the rate volume/surface is small. The surface (square) represents the loss of heat (on contact with cold air), whereas the volume (3 times) means heat gain. Their corporal density also increases their capacity to dive, which is vital for them, as the penguins’ food lives deeper in the ocean than that of the auks, which live in a shallower ocean that the Antarctic. It is still difficult to explain how they can dive so deeply with such a tiny body.
The two families never meet, for a very simple reason: between each zone is an obstacle they cannot go through: the tropics! Much too hot for them and lack on the preys they are feeding on. Maybe one day they will gain in adaptation and develop the ability to support the conditions of these warm oceans, like on the Galapagos, but it’s not the case yet…
Origin and evolution
I will not speak for hours about the origin of penguins, but it’s interesting just to have a look about the history of these birds. I told you at the beginning that they are really incredible birds as shown by their evolution, and I will rapidly explain why.
For years, travellers described penguins like “under-birds”, incapable to fly, a sort of half-bird, half-fish. Bouvet, a French 18th century naturalist, wrote they’re a “kind of duck swimming like a fish, and whose only difference is the beak like that of a crow”. That’s not really flattering !
In fact, the study of their origins shows that the Sphenicidae familiy is not only one of the most complex, but also one of the most successful on earth.
Even if incapable of flight, they have no similarity with ratite birds like kiwi or dodo, which could never fly. Actually, they come directly from tubenose and albatrosses, the best gliding birds in the world. Proof of this is the hypertrophied breastbone (which is not the case with ratite birds) and the horn-billed bill.
If penguins have lost their ability to fly (which didn’t happen over a few centuries: this evolution lasted millions of years), and have seen their body transformed so much, it’s because they adapted themselves to the environment; I’ll explain this later.
The different species of penguins
Since the first fossile was found (in NZ) 40 species of penguins have been identified.
Nowadays, there are 16 or 17 species, depending on whether one is considered as a full species or a sub-species (Schlegel penguin). These 16 species are divided into 6 genus :
Genus Aptenodytes : King, Emperor
Genus Pygoscelis : Adelie, Gentoo, Chinstrap,
Genus Eudyptes : Fjordlands, erect-crested, rockhopper, macaroni, royal, Snares Penguin
Genus Eudyptula : little penguin
Genus Megadyptes : yellow-eyed penguin
Genus spheniscus : magellanic, african, Humbold and Galapagos penguin
What brings all these species together (called the Impennes order: animals having wings witout quills, therefore unable to fly) is the fact that live in a sea that never exceeds 20°C (except for the Galapagos p.). The distribution of cold water comes from cold austral currents : the Humbold current going north on the west side of the American continent (reaching the Galapagos islands), the Benguela current on the west side of the African continent or the west Australian current.
In the Antarctic zone (including the continent itself and the sub-Antarctic islands), 8 species of 3 genus might be seen, in the Peninsula 4 : Adelies, Gentoos, Chinstraps (and Macaronis). Emperors are living on the Peninsula, but further south on the western side of the PA (on Dion Island) and in Snow Hill on the Weddell sea.
I’ll present you the species we’re able to see during our trip to The Falklands and south Georgia :
First group (Aptenodytes) : the great penguins
The King Penguin
Belongs to the 2 biggest penguins on earth with the Emperor : more than 1m high.
Weight and size of the adult varies from one colony to the other. In SG they’re bigger : 14-16kg.
Color of their feather are brighter than the Emperor, chicks have brownish down.
The most noticeable characteristic of the King are their breeding cycle : they breed 2 times out of 3 years, which is unique among the penguin and perhaps among all birds : brood last 12 to 14 months.
Parent lay 1 egg between November and march, according they’re early or late breeders.
It stays protected from the cold into the incubating pouch for 2 weeks, male and female take turns.
After 2 weeks, its down is thick enough to allow him take distance from the parents and walk around alone.
For 2 to 3 weeks more, parents feed it a lot, and the cheek will grow so quickly and so much that its weight will surpass the one of his parents about 10%
But little by little parent will come less often and at the end of September, around march-april, the chicks, gathered in crèche, will be abandoned alone for the following 5 months of winter. Adults will come only 3 to 4 times to feed them a little.
In spring, October, they come again more often. Chicks have lost a lot of their weight during this fasting period, and those which have survive will fatten quickly again.
In December-February, they’ve molt into their immature plumage and will join the see. They will come again only 1 year later to molt a second time to have their adult plumage.
King penguin live only above the Antarctic convergence, above 45°. They are about 2 millions pairs.
Second group : crested penguins (Eudyptes)
The crested penguins have all in common very special colored plumes on their head. In addition to this physical feature, they also all leave in huge rockeries, are all very noisy and aggressive, and above all, they have a strange breeding biology : they lay two eggs : a first small one, and later on a second bigger one, which is the only one which will hatch or give a living chick, irrespectively of food availability. Another common point to the crested penguin is that the chicks are nearly constantly brood by the male which fasts, and the female feeds the chick until it’s 3-4 weeks old, when it becomes mobile and joins the crèche.
The biggest of the crested (71cm high). Macaroni refers to the 18 century “Macaroni dandies”, British travellers adopting the Italian fashion of the time, that mean used to be dressed in very colorful clothes and wearing eccentric hats.
Macaroni have the more colorful plumes on the head, surely the reason of its appellation. They are the most represented penguin species on earth with 11 millions of pairs counted (very few in the Falklands, but numerous in SG).
They will reach their nesting site around sept-oct and build a simple nest. When winter comes, they leave the cold weather and reach more temperate waters, where they feed on krill and small fish. They don’t swim very deeply, but can cover quite long distance (500 lm).
After the biggest, the smallest of the crested penguins ( 45-55 cm).
Among the 6 species constituting the crested penguins group, the rockhopper are the only one whose 2nd egg will hatch and give a chick. This chick will never survive, but it will be born. So in the order of penguin, we can really see the stages of “evolution” : the brush-tailed lay 2 eggs, the rockhopper 2 too but one will dye, the other crested lay 2 but only 1 egg hatches, and the great penguin finally lay only 1 viable egg.
A very big colony is in the Falkland, where they can inhabit over very tall cliffs. Nesting on lava flows or rocky slope, the can climb on the stony steep slopes and jump in the sea from quite high, giving them the name of Rockhopper.
They live mostly north of the convergence, and the most southern will lay the latest. They live generally with colonies of black-browned albatross and can occupy abandoned truncaned nest. Rockhopper also cohabite commonly with other crested penguins.
They incubate for 3 weeks, female feed. After 3 weeks, chicks gather in crèche and are fed still for 2,5-3 months.
They feed on krill and fish, but can also take other food according of the availability the sea offers.
Their natural main predators are the skua, the Antarctic fur seal and the leopard seal, but they also suffer a lot from introduced animals (Flkld) like rats and cats, which take the egg.
Population is dramatically dropping, supposing because of famine. The rise of water temperature inducing shifting/transfer of krill population may be an explanation.
A sub-specie of Rockhopper exists further north in the sub-antarctic island : the northern Rockh. : even more eccentric with his long plumes.
Both Macaroni and Rockhopper are the only crested-penguins not endemic from NZ.
The 3rd group : the northern penguins (2 family - Spheniscus)
Because they live on the most northern latitudes of the southern hemisphere, they were also the first to be seen, and thus the first penguins to be observed. The family name “spheniscidae” was given after the name of the genus “Spheniscus”.
In addition to the northern latitude, they have all in common to lay in sheltered nest or burrow. That means that chick do not form crèche, but are brood by their parents, in a individual way.
We will be able to see one species of them :
The magellanic penguin. Magellanic penguin, like mainly all the other species of the genus, have naked skin around the bill and the eye ; The M. penguin is easily recognizable with its double-black bands crossing its white belly.
On the contrary of the true Antarctic penguins, they must evacuate heat in summer time. And because you know that no bird can sweat, they must thermo regulate in another way.
They incubate their egg in shelter to protect them against the sun and the heat and after to protect the chick against terrestrial mammals.
They breed from sept to april in up to 2m deep burrow on open beaches and grassy slopes. They lay 2 eggs, incubate for 40 days ; the chicks fledge when 2/2,5 months old.
Population : 1 million pairs.
The last group : the brush-tailed penguins (pygoscelis)
3 species constitute this group ; they all breed south of the Antarctic convergence.
Chinstrap Penguin, also called Bearded penguin. The second most important population of penguins in the world, with about 7.5 million pairs, maybe even more.
The Chinstrap belongs to the Pygoscelis family (meaning curving legs in Greek), or the brush tailed family, as well as the two following sp. The population of these 3 sp overlaps in the AP, with the Chinstrap being the median one.
The Chinstrap has a black strip under the chin and its face is white. The brownish eye and the rose-pink legs are the only patches of color on their body.
The Chinstrap is quite big (72 cm and 4 to 5 kg), and aggressive. They defend thoroughly their nest, and they can co-exist with the northern Adelie colonies. Their nest are very simple: only a little hollow in the ground with some stones to delimit it. This nest will be built all through the breeding season by the parents, and you will be able to see some of them carrying a stone in their beak. Chinstraps lay 2 to 3 eggs, each chick having the same chance of hatching. They eat essentially krill, and as don’t dive very deeply (40m) ; they catch sometimes small fishes and feed mainly during the night. They can cope with steeper slopes and higher elevations than the other brush-tailed.
Gentoo Penguin The Gentoo are less represented than the others : “only” 250 to 350 000 pairs have been counted. But we will see a lot of them, because they can be found as in the South Shetlands Island as well as on the AP.
It is very easily recognizable with the white tiangle over the eye and the orange beak. It is taller than both the other species of the genus (76 cm high – 3rd biggest penguin on earth), but what is characteristic of the species are the many differences existing WITHIN the species itself: .
The size : there’s a correlation between size and latitude ; the further north they live, the bigger they are.
The date of the egg-laying. It looks like the temperature of the water is a determining factor in this phenomenon. A delay of 6 months can be noted between “warm” and “cold” waters. For example, the nesting period occurs in June on some northern sub-Antarctic islands, like Marion (near Crozet), whereas the egg-laying takes place in December in the cool AP.
The food. There’s no real specific or typical food for gentoo : depending on the latitude where they live, they can eat krill, small fish or other crustaceans.
Gentoo never go too far away of the colony: they stay in the inner limit of about 30 km, spending a lot of time hunting. They have a nest a little bit more elaborated than the others: the nest lies usually on the top of a kind of hill, and is constructed with small stones and sometimes algae. Parents lay 2 eggs, with the same chance of hatching.
They are shy and don’t fight roughly, so they may be weaker than more combative species. But they are also very curious, and you will probably see chicks coming close to you to feel you. The parents take care of their chicks even after they have molted, and go with them in the sea to teach them how to fish.
Adelie The Adelie penguin was observed for the first time by an expedition led by Dumont D’Urville, and was named after D’urville’s wife: Adèle. The name was also given to the land discovered in 1840, at the south part of the continent.
The Adelie are also easily recognizable: you can distinguish the white circle around the eye (that expand, dilate when stressed), and a erectile crest on the top of his head ; only adults possess this feature, which plays an important part in the social behavior. They are about the same size as the Chinstrap (75 cm), and their weight can vary between 3 to 8 kg, depending on the period (fatty before molt, thin after).
But the Adelie have a big difference in comparison to the other pygoscelis : they are the only ones nesting on the continent (with the Emperor). Actually, the ones we shall see are the most northern one. The majority lives much further south. This suppose that they must face an even shorter summer : their breeding cycle is then accelerated : the male come very early in the season and walk great distances on the pack to reach the nesting place: from 30 to 100 km.
They are much better equipped to support colder temperatures: they have longer feathers, and these even cover the base of the beak. They get mature between 3 to 8 years old. But they also need a snow-free place to nest.
The adults abandon their chicks early, before they have completely molted. This force them to go to the sea (even with still some down) because of the hunger.
Many surveys have been led on this species and its behavior is quite well known. The sp. is quite aggressive toward the other individuals but very shy with humans. You will notice this easily; if you approach them too closely, the white circle of their eye will enlarge, and the crest will erect. So immediately go backwards to avoid them being stressed.
The Adelie lay 2 eggs. Once the chick have joined the sea for the first time, they won’t go back on earth before 2 or 3 years ! They also feed on krill and fish. They can at depth of 10 to 15 meters (up to 175m) or between 35 to 45m.
2,5 million of pairs.
Penguin : shapeless birds ?
I said earlier that, far from being “under-bird”, penguins are on the contrary champions of adaptation. In fact, they’ve managed to live in the most extreme continent on earth. I’ll now speak only about those 4 species I’ve just described, and not about the whole family (especially not the subtropical ones, whose habits and adaptations vary a lot).
The Antarctic continent is the coldest on earth : average of -50°C inside the continent in wintertime (the coldest temperature ever measured on earth was on the continent, at the Russian base of Vostok : -89,6 °C), and the summer temperatures do not go above -20°C).
Winds can easily reach the speed of 200 km/h (the world record is 320, before the anemometer broke !) Blizzards (wind charged with ice) are common.
the austral ocean is constituted by the strongest current on earth : twice as strong as the Gulf Stream and 400 times stronger than the Mississippi river.
97% of the continent is covered by ice and snow all year round, preventing any mammals (which mean potential prey) from living there. Equally, almost the unique vegetation able to grow are mosses and lichens which doesn’t represent any food.
the continental plateau is exceptionally narrow and deep, limiting the presence of surface fishs.
So we can hardly wonder how it is possible to survive in such conditions! But… it is!
First, penguins had to adapt to the only environment that provides food: the ocean. As there were no predators on land to hunt them (we’ll see later that they have to go ashore), it was unnecessary for them to keep the ability to escape through the air. So a perfect adaptation to aquatic life became vital for them.
So penguins became excellent swimmers
on the contrary to flying birds, penguins have heavy and dense bones, which allow them to dive deeply (hollow bones lighten the body to fly and break at immersion into the water) ;
the neck is reduced to improve the profiling under water ;
the tail is short, close to the feet, and is used as a rudder;
when immerged, the heart rhythm varies a lot : it increases when the bird enters the water, but then decreases to spare oxygen in the lungs, blood and muscles.
the trachea is reinforced to support the important pressure occurring when diving, with the presence of a median partition inside.
like all marine birds, penguins have 2 nasal glands at each side of the eye, allowing to eliminate the excess of salt they may absorb with their food. This brine forms a little drop of water, running along the beak. So each time you see a penguin shaking his head like this, he’s getting rid of this little drop!
penguins are short-sighted on land, but see very well in water.
their tongue is very rough, and their mandible strong so they can catch slippery prey and swallow them easily.
Thanks to this morphology, penguins are excellent swimmers. They swim easily at 10 km/h, and some of them reach the speed of 30. Macaroni penguins never dive very deep (less than 30 meters). Gentoos dive between 30 to 100m, Adelies have been measured at a depth of 200m, King at 300, and the record goes to the Emperors with a depth of 525m. The dives last from 1 to 2 minutes to, again for the Emperor, 25 mn. When penguins swim fast under the surface of the water, and when turbulences might break them, they jump out of the water, like dolphins or porpoise. This also allows them to avoid predators. We may see this phenomenon close to the beach as well as offshore.
Such knowledge is possible through studies made on penguins, with the placing of a transmitter under the bird’s skin. Previously, the transmitter was put around the wing (because penguin have too short legs to put a ring on them, but it has been noted that they were disturbed in their movement at this strategic place of their body.)
Penguins also had to adapt themselves to cold
Cold is very important ashore, but much more in the sea, where penguins spend 75% of their life time, if not more. The feeling of cold is 45 times higher in the water than in the air (the air is isolating). For example: you can easily live at a temperature of 0° - 1°C… But if you fall into water at the same temperature, your life expectancy is about 5 minutes (never fall out of the zodiac !). That means also that penguins, because they are moving constantly in a 0°C environment, can bear air temperatures of up to -45°C... How do they manage to support this?
Feathers are short, thick, rigid like scale, and very dense (10 feathers per square cm), with no naked skin, except for some species around the beak and on the brood patch. The air is actually imprisoned in the feathers, forming an insulating layer. Each year penguins molt to renew totally their feathers (we’ll talk about this later) and preen them consciously.
The color of the feathers also contributes to a less important heat loss. The black color on the back absorbs any of the sun rays and heat the body. Not the only explanation of the B&W : the other one is to avoid their predators : while swimming, their white belly can’t be well distinguish from the waves for a predator coming from below them, and for a bird flying above them, the dark black is also camoufladed in the holes of the waves.
The resistance to cold is improved by the presence of a big layer of blubber, which is unusual among birds .
4th and possibly: body temperature
Penguins have the capacity to modulate the temperature of their body, depending on their environment. On land, their temperature varies between 37 to almost 39°C, whereas when they dive, it drops to 20°C, in order to limit the effort of the body to warm up. It’s been said that what a penguin supports at -10°C is equivalent to what a human being can support at 27°C…
Currently, penguins cannot breed offshore. Like all the other marine birds, they need to leave their favorite environment to join land to nest and breed.
So penguins became also very good walkers
They’re not skilful, but are able to move on very big distances, even on rough terrain. The record goes again to the Emperor, who covers a hundred km to join his breeding place.
So their anatomy is also adapted to walking :
the tarsometatarsus (the main bone on the foot) is large and flat, to facilitate the standing position (and receive the egg for the Emperor), and the claws are strong to unable them not to slide onto the ice or the rocks. the underneath of the sole is covered by a anti-dragging structure, made of little pickles.
By walking the flippers are used as a balancing pole.
Adelies and Emperors, who can live on snowy ground, use their profiled silhouette to slip on the ice, sparing effort (it’s called “tobogganing”).
As I just told you, penguins, like the other marine birds, only come ashore to breed. Once mature (between 3 to 7 years depending on the species), they leave the ocean and look for a dry place, free of snow and ice. Nesting and breeding habits vary a lot, so it’s difficult to give general description. They are nonetheless more or less the same for the brush-tailed sp, and I will now focus on these 3 sp.
An advanced social organization
According to species and localization, colonies can vary from some dozen of pairs to hundred of thousands of them. Available space being reduced to the minimum in the polar regions, several species can cohabit, even understand each other. Cephalic coloration plays an important role in the recognition of the species, especially during breeding time.
When individuals reach the ground, their aim is to find the right partner to form a pair. It’s the time of nuptial display, where gestures and calls are determining. Once formed, the couple has to find quickly the best place to establish the nest, which is different according to the species : a simple hole in the ground on the beach, at the top of a hill, on a protected slope, on an exposed beach...But the nests are rarely very elaborate, only made with pebbles they collect around them.
Penguins are usually faithful to their breeding place, returning each year to the same place, and normally to their partner, at least during a couple of seasons.
Mating generally produces one to three eggs. The period of laying varies slightly : the whole breeding cycle must be accomplished within the summer, between end of November to end of January.
Both parents contribute to education
After laying their egg, very demanding on energy, the females return to the sea to regain force. So the males assure the incubation of the eggs at the beginning, and then both parents take turn (between 30 to 60 days) ; the incubation is possible thanks to a well irrigated brood patch.
Once born, the chicks grow quickly, because both parents feed them a lot, going one after the other constantly to the sea to catch food. When they reach the nest, they regurgitate, thanks to stomach contractions, a kind of liquid into the chick’s beak. This food is astonishingly fresh. Studies have shown that this is due to a specific enzyme called sphenicin, preventing the food from rotting. And this is especially true for the emperor, who hunts for weeks miles away from the colony. Without this enzyme, food in their stomach would already be digested.
The constant movements to the sea exacerbate the aggressivety of the individuals, and we will see that they fight and shout all the time, looking for their chick (and vice versa).
Chicks depend entirely on their parents when they’re small in terms of food and heat. The more they grow, the less this is true, and after 3 to 4 weeks they are big enough to thermo regulate by themselves ; both parents can then go to the sea to forage, and chicks stay on their own, forming what is called a nursery, or a crèche. At this time, chicks still don’t have their definitive feathers, and parents and chicks only recognize each other through their call.
Young penguins have to reach the sea before seaice covers the ocean. So they have to change their down for real feathers : it’s the time of molting. Adults molt after them, and this period is critical for them, because for the second time of the “year”, they have to fast. Effectively, whereas other flying birds molt progressively, changing one feather after the other, penguins lose their feathers all at once. They’re then unable to go to the sea for 2 to 3 weeks. After the moulting, they reach their lowest weight. Very sensitive time.
But once molt is over, they can reach the ocean again, where they will spend the rest of the year, never coming ashore again.
An ocean of food
So penguins spend the majority of their life in the sea, eating, and living very far away from the colony. This is especially true for the Antarctic species, because sea ice doubles in winter, making the coastlines inaccessible for thousands of kilometers.
Penguins eat essentially krill, cephalopods and, for the bigger one, fish. They eat what the majority of the others animals eat, the krill, which represent 14 millions of tons of crustaceans (krill), and 3 millions of tons of fishes and squid.
Just a word about krill, because it’s an incredible animal…
The krill living in Antarctica belongs to Euphausia Superba family and is a 3 to 6 cm crustacean ; so it isn’t microscopic, and maybe we’ll find some of them on the beaches. It’s orange-pink like a shrimp, although it doesn’t belong to the same family. And it can reach unbelievable quantities. Actually, extrapolation affirm that they represents about 600 000 billions individuals, making them the most numerous species on earth. This number means more than 650 million of tones, so more than human weight. Because of the decreasing numbers of whales, it’s even said that krill population is increasing, but nowadays they’re hunted by humans, so it’s not sure… Krill lives in huge shoals, eating phytoplankton growing under the pack ice, and laying billion of eggs (200 to 300 000 eggs per female).
So we can say that penguins swim in an ocean of food !
Penguins are prey too !
But penguins are not the only ones living in the sea, and not the only ones needing to eat. They themselves are a prey for a certain number of predators, and this is true whether they’re offshore or ashore.
Threat comes from the sky. There are skuas, giant petrels, gulls, and... sheathbills.
In the Antarctic zone, skuas are very aggressive to penguins, and they attack immediately each isolated, weak, wounded or young penguin. This is the reason penguins are highly gregarious.
Gulls and petrels are more opportunists, the eat mainly eggs and carrions but occasionally the GP can predate on chicks when hungry.
The sheathbill doesn’t attack directly but is also a tough enemy ; actually, his method is defined as kleptoparasite : he will catch the food at the exact moment the penguin is regurgitating it to his chick. It does not look serious, but it means the penguin has no other choice to reach the sea again, while the chick has to wait. When the colony lies at hundred of meters far away from the beach, it can be really problematic…
The most dangerous predators are killer whales and leopard seals.
The leopard seal can be 3 to 4 m long and weigh 400kg ; he can swim up to 10km/h and when skilful, eats 6 penguins in one hour. His teeth are planted to filter krill, but in summer his favorite prey are penguins – it can catch up to 6 an hour when fit. The most critical moment for the penguins is when the chicks go to the sea for the first time and when the adults reach the water after the molting, because they are very weak.
Last threat: Humans
Last but not least, the enemy was and still is Human.
The Antarctic has always ever been a virgin place, with no human inhabitants. Penguins are not adapted to escape or to defend. When the first explorers came, and then whaleboats (end of the 18th c.), they were such easy prey that their number dropped dramatically. However, they weren’t hunted for their food, but for their fat. Indeed, I told you that they have a thick layer of fat, which is good fuel for the boat engines. (the rumor saying that penguins were not even killed before being put in the burning machine like a simple piece of wood is false).
Extinction failed because of the discovery of… petrol ! It became much easier to use the black gold than living penguins, and in association of the development of the protection of biodiversity, the population of penguins rapidly increased again. The irony is that now petrol represents a new serious threat because of the oil slicks.
Another new element was the development of scientific stations where garbage wasn’t destroyed for many years, and starting several years ago, tourism activity, leading masses of people into virgin places. The ecosystem is so fragile that bad organization can have dramatic consequences on wildlife. Fortunately, IAATO was established very early by the tours operators. Thus it is important that the strict rules of IATO are followed and we must constantly be aware of the extraordinary environment we are entering.
However, when we know this and take it into account, there is no reason why we should not benefit from the amazing beauty of the Antarctic, because it’s just fascinating.