Why penguins do not fly?
In the evolution of the animal world, the rule was formed: it is impossible to achieve perfection in flight, running and swimming at the same time. Therefore, penguins are one of 18 species of birds that completely lost the ability to fly. Of all the modern birds, they most fully adapted to habitat in the water environment, because the main food is a fish.
And penguins learned to dive to a depth of more than 20 m, developing speed up to 36 km / h (with the usual "cruising" 10-14 km / h). May be under water over 18 minutes. And with dangers, jump ashore by 1.5-2 m in height. Of course, such indicators would be impossible without some morphological changes.
Gagars, loosening, cormorants, ducks and other birds, which are also well swimming and dive, row with feet, transformed into oars. Therefore, their lower limbs are strongly shortened, and the fingers are connected by a swimming pool or cut off with leathery swimming blades. As a result, these birds are completely clumsy on land, but quite capable of flying.
Penguins also use legs as steered, due to which they are quite moving on land. But at the same time they are the only ones who row wings. Here they were transformed into shortened elastic flips, and the sternum appeared a clearly pronounced keel, to which a powerful musculature is attached. Since water resistance is more than air resistance, the same energy is spent on the lifting of the wing as the lowering. Therefore, the blades of penguins, to which the muscles are attached, which is responsible for the rise of the wings, began to occupy a large area compared to other birds. The body of the spine has become more movable. And due to the fact that the load was redistributed, change and in the muscular system.
Another obvious distinction of penguins was the change in bone density. The rest of the birds they are tubular, which makes the skeleton easier and allow you to fly or quickly run. And penguins bones are like mammalian bones.
So they swim well, run well, but absolutely can’t fly.