Penguins are very loyal to their feelings. Like humans, penguins are monogamous and very devoted. It is said that when penguins propose marriage, they will also send a small pebble to their partner as a token of affection.

Penguins also have fossils. Not only those ancient creatures have fossils, but penguins also have fossils - after all, it also lived in prehistoric times. At present, the earliest penguin fossils discovered by humans came from about 60 million years ago, almost in the age of dinosaurs, proving that birds and dinosaurs are likely to be close relatives.

Penguins' flippers are bare, and even so they can run in icy snow without getting frostbitten. This is because penguins have a unique blood circulation system: countercurrent heat exchange. When standing on ice, there is a countercurrent heat exchange between arterial blood and venous blood. The warm arterial blood can transfer heat to the cold venous blood, so that the temperature of the blood flowing to the feet and the heart will be similar. The temperature difference between the soles of the feet and the ground is also reduced, so that the heat lost is reduced, and there will be no frostbite.

Penguins are birds, why can't penguins fly? In fact, in ancient times, penguins, like ordinary birds, could fly. It's just that they migrated to the Antarctic because of the changes in the crust. Since their living conditions do not require flying, now their wings have degenerated and they can never fly again.

Although most penguins are in the Antarctic, don't think that penguins cannot survive in the equatorial regions. The Galapagos penguins in the Colon Islands are the only penguins to set foot in the northern hemisphere and the only species of penguins in the equatorial zone. For these penguins, maintaining a cool body temperature is a test of wits.

When it's hot, penguins stretch out their fins to increase heat loss. And those penguins that didn't breed stopped staying on land, opting instead to jump into the water.

Penguins are also afraid of the dark. But not because they have poor eyesight, but because they are afraid of being eaten at night. The natural enemy of penguins is seals, and seals mostly come out at night to catch penguins and rest at sunrise. So in order to survive, although there are more fish and krill to catch at night, the penguins still prefer to hunt during the day.