Why does the swallow's tail split? Fairy Tale

One day, the Snake made a complaint to all living and non-living beings on earth:

— My Creator has made me inferior to all of you. I have no limbs. I cannot lift my head and am left crawling on the ground. I do not even know what to eat or what to leave. You are all of one language, while I am of a different tongue. As I ponder, I realize that among living and non-living beings, I am the most unfortunate. None of you wish to help me. You don't even comfort me with words like, "You have suffered greatly, and such ones are always fair; you can be a king to us all," — and with that, he shed tears of blood and wept profusely. All living and non-living beings expressed pity for the snake and considered his grievances justified, saying, "He may not be seen, but he can divide the black thread and be our wise counselor," and they elected him as their king. Year after year, day after day passed by.

One day, the Snake thought: "If I become king of the whole world and take all power into my hands, I would live even better. Instead of eating whatever food appears before me, I would feast on the sweetest blood of all living beings," and he began to fantasize. He summoned those who could distinguish the taste of blood. The Mosquito, fluttering its two wings, and the Fly, with its snout raised, came along with all those who wished to please the king. Among them, the king addressed the Fly and the Mosquito:

— Travel the world, taste the flavors of plants, and suck the blood of all living and non-living beings; not only these, but also taste the hard stone and soft soil. Ensure that the sweetest thing in the world becomes my food from now on, — he decreed, and sent them off to explore the entire world. Days passed, and the time he had set for them approached. The Fly, due to its weakness, hid under the grass when the wind blew, and while singing softly during calm moments, fell behind. Meanwhile, the Mosquito, having learned about the sweetest plants and beings, was fluttering and singing toward the king when it encountered the Swallow.

— Yes, my friend Mosquito, we heard you went to find the sweetest food for our king; did you find it? The Mosquito, looking down on the Swallow, ignored its question and dashed off.

— Ah, ah, I understand, I understand! You are lucky; you found what you were looking for, my friend... You are indeed a true man! I know your agility and your boldness, which does not shy away from anything. We will now tell all the winged creatures about this quality of yours, — the Swallow said, trying to flatter the Mosquito. Flattered by this praise, the Mosquito, in a daze, said:

— Do you know whom I found for our king's meal?

 — Oh, my friend Mosquito, what do I know? Except for the size of my body, my mind is not small, is it?! You are the king's advisor. Come on, tell me, whom did you find for our esteemed king's meal? The Mosquito, growing excited, said:

— The sweetest food suitable for our king in the world is human blood. “Hmm... Is an intelligent and cunning being like a human going to be prey to a half-witted creature like me?” thought the Swallow, coming up with a plan.

— Isn't my short-sightedness the problem here, my lord Mosquito! I have been uncertain about believing that human blood is sweet. My mother used to say, “The tongue of one who finds and tastes the sweetest blood in the world will be marked with a golden seal.” Come on, show your tongue and let me see your seal! Just seeing the golden seal would be a great solace for us. Flattered by this praise, the foolish Mosquito:

— If you want to see, then look! – he said, sticking out his tongue. The Swallow quickly swooped in and bit off the Mosquito's tongue, leaving him unable to speak and buzzing as he flew toward King Snake. “Farewell, your tongue has been severed. Your mouth has been filled with sand. How will you explain the sweetness of human blood now?” thought the Swallow as it flew after him. The Mosquito buzzed in desperation, trying to say something. However, he could not explain anything to the Snake.

— Has his tongue fallen out of his mouth, or has he gone mad? Do any of you understand what he is saying? – the Snake asked those present.

— Quite understandable, my king! – the Swallow replied.

 — Before I perish without seeing the night, if you understand anything, tell me what he is saying!

— Buzzing around, I traveled the entire world. But I found nothing other than the soil from which all kinds of plants grow, - says our king! Even though his tongue cannot speak, the Mosquito, with ears intact, felt his soul almost leaving him upon hearing this. He buzzed around, stinging the Swallow two or three times before flying to the Snake and bursting into tears.

— Ah, ah, it is you who has cursed his tongue, – the Snake said as he lunged at the Swallow. The Swallow took flight. The Snake only managed to bite the Swallow's tail. From that day on, the Snake started licking the ground, and the Mosquito continued to buzz. Humans began to kill snakes on sight, crushing their heads. The Swallow, fearing the snake, befriended humans, building its nest on the roof of houses, but its tail remained split, becoming two-pronged.