"Most experts agree that yodeling was used in Alpine folk music in the Central Alps as a method of communication between herders and their stock or between Alpine villages, with the multi-pitched "yelling" later becoming part of the region's traditional lore and musical expression. The calls may also have been endearments shepherds used to express affection to their herds. The earliest record of a yodel is in 1545, where it is described as "the call of a cowherd from Appenzell".
It is thought that yodeling was first introduced to the United States by German immigrants in Pennsylvania in the early 1800s. As the new settlers traveled south through the Appalachian Mountains and beyond into the Deep South they came into contact with Irish immigrants, Scandinavians (practictioners of a unique yodeling called kölning), and other nationalities including African slaves who communicated with "field hollers", described by Frederick Law Olmstead in 1853 as a ‘long, loud, musical shout, rising and falling and breaking into falsetto’. German yodeling may have converted southern field hollers into a more musical form and combined them with Irish narrative ballads, resulting in the unique form of the yodeling tradition in America. But it was Jimmie Rodgers, who combined the southern Black blues with the yodel in the 1920s, who introduced and popularized the American yodel in the United States." --Wikipedia
What is jodeling and what is field hollers, one could safely assume, goes back to the dawn of shepherding and farming itself, on all continents; though I would like to think its origins were even more primal than communication between people (or people to animals) over long distances: more like the spontaneous banishing of ghosts and shadows from the lonely hills, pushing back the boundaries of fear (it probably also made the animals produce more wholesome milk), declaring mastership over nature as children redeemed in Christ - like Tom Bombadil with his constant singing and pouncing from place to place.
That, I think, is the true origin - which is not natural, like art. To use William Golding's Lord of the Flies as an example: what is natural is to tell all the others in the deserted primal jungle island to shut up and to satiate them with meat and to cut off the sow's head and spit it on a pole as a peace offering to the Beast.
What is not natural is, in the midst of mounting tension and primitive chaos, to take up the conch and, standing in one's dignity, give wind to it, for all to hear and gather up their attention to something higher - precisely when fear would tell one to be practical.
Art is an extraneous exertion of the soul.
Zäuerli I guess is a Swiss jodeling group. I definitely could not listen to it all day, but I do like it. I first came to know the sound through Werner Herzog's at times ecstatic, at times pretentious film Heart of Glass. This is the beginning of the film: