Why is it called "blowing the bull's skin" instead of "blowing the sheep's skin"?

Modern people often use "吹牛皮" to describe bragging.

That is really vivid and lively.

But have you ever had any doubts?

Why not use the metaphor of blowing sheep's skin or pig's skin?

This is a sheepskin raft , an ancient means of transportation on the Yellow River with unique regional and ethnic cultural characteristics. Its characteristics include shallow draft, no fear of running aground or hitting reefs, and flexible and easy operation.

What? A sheepskin raft? It is obvious that it is a raft, but it is hard to believe that the wooden frame is made of sheepskin. Pigskin is more likely.

The reason why pigskin is used is because of its bulging appearance. In fact, pigskin rafts are mainly used in Gansu, Qinghai and Ningxia in the upper and middle reaches of the Yellow River, and most of the users are Hui people. Animal husbandry is the main industry there, especially cattle and sheep, but pigs are rare (Hui people think pigs are dirty, so they don't eat pork and don't raise them).

These places have complex terrain, high mountains and steep cliffs, and herds of cattle and sheep, which also provide sufficient raw materials for making rafts.

The production process of sheepskin raft

The reason why the sheepskin raft has a bulging shape is due to its manufacturing process. The manufacturing process of the sheepskin raft is not simple, and the locals have even made up a jingle for it.

The jingle for making sheepskin rafts

Kill a sheep, peel off its skin,

Cover up the hair and apply a layer of oil.

Expose for a month, take a breath,

Tied in rows, they can rival warships.

Drifting there for decades, free and easy like a god.

When making it, you need to open the sheep's neck and slowly peel off the whole skin. This process is called "huntuo". It is worth noting that the skin bag should not be scratched during the whole peeling process. After processing, it is blown full of air, and then filled with sesame oil, salt and water. Then the head, tail and limbs of the skin bag are tied tightly and dried. The dried skin bags are tied under the square wooden frame one by one, and the leather raft is made.

Now you should know,

What’s the reason why the sheepskin raft is bulging?

The inside is filled with air, the purpose is to increase buoyancy like a life buoy. In the era when there were no air pumps, it was all done by blowing with the mouth. Generally, the sheepskin tire needs to be blown 60-70 times, which is quite laborious.

At this point in the story, you must be asking me, I have been talking about the sheepskin raft for a long time, so what does it have to do with bragging?

It is said that at that time there was a man who claimed that he could not only blow up a sheepskin raft, but also a cowhide raft. Later, someone really brought a cowhide to him to blow up, but the cowhide was too big, hard and thick, and it couldn't be blown up no matter how hard he tried. Later, people used the term "boasting" to describe people who like to brag.

When making a cowhide raft, it does not need to be inflated. Instead, it is filled with lighter goods such as wool. If such goods are not available, it will be filled with hay, so the cowhide raft is also called a "grass raft".