Penguins may be the first bird you know.

Penguins may be the first bird you know, in cartoons, picture books, and stories.

We know that the numerous and large land masses on the earth are almost all crowded in the northern hemisphere, and the southern hemisphere is almost a water world. Penguins travel back and forth in such a vast water world and reproduce. Penguins may be the most special birds in the world. They are called birds, but they disdain to fly in the sky. Their body shape and living habits are more like fish: they have streamlined bodies like fish; they have fin-shaped wings like fish; they have the same color scheme as fish - when they swim in the water, they have a black back like deep water when viewed from the air, and a white belly like the sky when viewed from underwater; they also chase various planktons for prey like fish; they follow the ocean currents like fish and swim long distances in the vast ocean... This evolutionary idea of ​​"everything is aligned with fish" is unique in the bird world.

Penguin is a general term for all birds in the order Spheniscus and family Spheniscidae. This kingdom has 6 genera and 17-19 species. The largest members are all from the genus Emperor Penguin, which has 2 species - Emperor Penguin and King Penguin. The Emperor is the largest, followed by the King. The species with the largest number of individuals all belong to the genus Adélie, which has 3 species - Adélie penguin, white-browed penguin (also known as Gentoo penguin or Papua penguin) and chinstrap penguin. The main breeding grounds of these 3 penguins are in Antarctica. Together with the Emperor Penguin, which also breeds in Antarctica, these 4 species are the only true Antarctic penguins in the entire order of penguins. Those who think that penguins can only be photographed in black and white should pay attention at this time. The family introduced below is the most colorful in the entire penguin world, and the beauty-loving penguins who all wear cumbersome ornaments are the crested penguins. They are a large family, originally there are 6 species - rockhopper penguins (also known as crested yellow-browed penguins), Se Island yellow-browed penguins, yellow-browed penguins, white-cheeked yellow-browed penguins, upturned browed penguins and long-browed penguins (also known as Macaroni penguins). Later, people found that the breeding grounds of rockhopper penguins in different regions are very different, and it seems that they can be divided into two independent species - northern rockhopper penguins and southern rockhopper penguins. Therefore, some people now say that this family has 7 species. The distribution of the ring penguin genus is relatively north, and the members who are least afraid of heat are all in this family. There are 4 species, namely, the Canadian penguin, the Peruvian penguin (also known as the Humboldt penguin), the South American penguin (also known as the Magellanic penguin) and the South African penguin (also known as the spot-billed ring penguin). The smallest member is classified in the genus Little Penguin. Originally, there was one species, the Little Blue Penguin. Later, some people advocated that a subspecies of the Little Blue Penguin with white edges on its wings be promoted to a species, the White-fin Penguin, so now there are two species. The yellow-eyed penguin on the island of New Zealand has the most special appearance, which is very different from any other genus of penguins. It occupies a genus alone, the Yellow-eyed Penguin. The entire penguin kingdom divides up all the continents of the Southern Hemisphere. The division of its sphere of influence is as follows: the southern tip of the South American continent and the African continent and its affiliated islands are mainly occupied by members of the Ring Penguin family; the Australian continent and the coast of New Zealand are occupied by the Little Penguin and the Yellow-eyed Penguin; the Crown Penguin occupies the various small islands in the Southern Ocean; the cold Antarctic continent and its surrounding areas are the main camps of the Adélie Penguin and the King Penguin. Well, from the equator to 78° south latitude, this seemingly clumsy fat bird can be found on almost all continents and major islands in the Southern Hemisphere.

From this point of view, the world map of the penguin kingdom seems to be based on the South Pole as the main perspective, and it is most appropriate to draw a circular map with the South Pole as the center and the equator as the circumference. If you mark the distribution locations of various penguins on this map, you will find that the coast of Antarctica and the surrounding islands are the center of this kingdom, where the "emperor", "king" and most of the kingdom's "subjects" live; on the periphery of this center - the Southern Ocean, the southern edge of the continents in the southern hemisphere and the scattered islands, there live a large number of "tribes". Although the number is not as large as that of the kingdom center, the appearance and lifestyle of their "subjects" are diverse. Further out, there are some expedition families that have spread out sporadically. What exactly caused them to have such a distribution? In addition to the "continental drift theory" (the ancestors of penguins all came from the coast of the Gondwana ancient land, and later the ancient land split and drifted in different directions, and the species spread accordingly. Today, the continents where penguins are distributed are all part of the original Gondwana ancient land without exception), I naturally thought of water temperature. As we all know, Antarctica is the world's cold center. In the coldest months of June to August in the Southern Hemisphere, about 20 million square kilometers of sea area is covered by sea ice, accounting for almost 30% of the ocean area south of 40° south latitude. Even at the end of February when there is the least floating ice, there are still 3.5 million square kilometers of sea ice fields preserved. The sea ice surface that grows and disappears with the seasons throughout the year is nearly 17 million square kilometers. It is in this 17 million square kilometers of ocean that more than half of the world's penguins live. And do penguins outside this range also need cold water? I overlapped the map of the penguin kingdom with the ocean current map drawn from the same perspective, and I made an amazing discovery - most of the areas occupied by temperate penguins overlap with the range affected by the cold current in the Southern Hemisphere! The specific situation is as follows: the distribution area of ​​penguins distributed in the African continent, the Australian continent, and the New Zealand sub-Antarctic Islands overlaps with the areas affected by the westerly drift; the distribution area of ​​penguins distributed on the east coast of South America overlaps with the areas affected by the Malvinas cold current, and the distribution area of ​​penguins on the west coast overlaps with the Peru cold current; along the Peru cold current all the way north, it eventually affects the waters of the Galapagos Islands near the equator, which happens to be the home of the only tropical penguin, the Galapagos penguin. It can be seen that the spread of the penguin family, in addition to drifting with the continent, has always been accompanied by cold currents. They feed on plankton that reproduces in large quantities in cold water and live on the coastlines of land and islands where the cold current passes. Because the cold current disappears near the equator, their pace of spreading northward also comes to an abrupt halt - at the equator, all cold water masses are replaced by warm equatorial ocean currents. In the end, the power of the penguin kingdom stops at the Galapagos Islands and does not enter the oceans of the northern hemisphere. Coincidentally, according to my observations in the Arctic region and the coastal areas of the Northern Hemisphere for nearly 10 years, puffins, birds that look and eat very similar to penguins, also have a distribution characteristic of spreading from the edge of the polar region to low latitudes and finally stopping at the edge of cold water. This type of bird has indeed evolved into individuals (the great auk) that are also black in body, white in belly, fat and cannot fly. Is this just a coincidence?

Rockhopper penguins encountered off Cape Horn in southern Chile

The origin of penguins is also confusing, because penguin or penguin-like bird fossils have been unearthed in almost every continent in the southern hemisphere. However, like all bird fossils, they are precious and rare (the conditions for the formation of fossils of bird remains are very harsh). Although the fossil materials currently available are very fragmentary - those big and small, tall and short, fat and relatively fat, long-beaked and short-beaked... It is still difficult to piece together a clear and complete "penguin evolutionary tree" from the remains of penguins, but according to the different strata where these remains are located and the order of deposition of these strata, people can still see a clue: penguins seem to have experienced a process from small to large, and then to small.

The first penguin fossil ever discovered, as recognized by the scientific community, was found in limestone formations near Kakanui on New Zealand's South Island. It was obtained by a government worker named Walter Mantell while traveling in late 1848. The fossil, a bird ankle bone (incomplete, lacking a pulley or toe projection), was later sent to England, where it was discovered by Thomas Henry Huxley, a famous British naturalist known as "Darwin's fighting dog."

Henry Huxley, who was pleasantly surprised to find that the ankle bone fossil belonged to an unknown ancient penguin that lived 23 million years ago. He named it Palaeeudyptes antarcticus, which means the winged diver of Antarctica, and published it in the Quarterly Journal of the Geological Society in March 1859. The biggest problem with the discovery of extremely incomplete fossil specimens is that it gives people a wide range of imagination. Based on the thickness of the ankle bone, people at that time speculated that the penguin could reach 8 feet (about 2.4 meters) when it was alive, but judging from the ancient penguin skeletons we have collected now, this value is greatly overestimated.

White-browed Penguin

In the following 100 years, more than 20 species of ancient penguin fossils were discovered in New Zealand, Australia, South America and Antarctica. The time span of penguin life was from the middle of the Paleocene to the end of the Oligocene (about 62 million to 23 million years ago). In the 1980s, good luck once again came to the beautiful and peaceful South Island of New Zealand. About 65 kilometers north of Christchurch, there is a small river called Wapara. Brad Field of the New Zealand Geological Survey found a layer of marine sediments containing black mud in the early Paleocene strata of the Cenozoic Era cut off by the river. This layer of sediment is more than 60 million years old, not long after the Mesozoic era when the dinosaurs became extinct. With his keen professionalism, he discovered precious penguin fossils in that layer of sediment and immediately handed them over to R. Ewan Fordyce, a professor in the Department of Geology at the University of Otago in New Zealand for research. In 1990, Euan Fordyce and Craig Jones published some information about these fossils, but unfortunately, these fossil materials were still not enough to describe more details of this amazing animal. Later, Al Mannering, a paleontologist at the Canterbury Museum, discovered more Palaeocene penguin fossils in this layer, and more and more fossil evidence provided strong support for Professor Fordyce. Soon, Euan Fordyce's graduate student Dr. Tatsuro Ando conducted a more in-depth study of these fossils, and then the teacher and students jointly published a more detailed report, confirming that these fossils are the oldest new genus of penguin birds discovered by humans so far, named Waimanu penguin (Waimanu), the word "wai-manu" used in the genus name comes from the local Maori language, meaning "bird in the water". In recognition of Al Mannering's work, the first species of Waimanu penguin discovered was called Waimanu manneringi, which lived in the middle Paleocene (about 62-60 million years ago).

Emperor Penguin

Compared with modern penguins, Waimanu penguins have very long necks and beaks, and more complex wings that can be folded into their sides like modern birds. From such wings and its plump body, we can judge that they have given up the right to fly and turned to the water. This is a bit like the weak-winged cormorants on the Galapagos Islands today. Due to the abundance of bait and the lack of natural enemies, the weak-winged cormorants took the initiative to give up the sky and turned to the embrace of the sea. Although their wings still retain the appearance of flying birds, they have become short and weak and cannot fly. The above evidence strongly shows that penguins also evolved from flying birds, which completely breaks the argument that some people say that penguin wings evolved directly from the forelimbs of reptiles and have never had the experience of flying.

Further reading: "Games on the Ice Continent"