The dahu's principal distinguishing characteristic is that the legs on one side of its body are shorter than the legs on the opposite side, to facilitate standing on and walking on steep mountain slopes. In practical terms, the dahu's asymmetrical limbs allow it to walk around the circumference of the mountain in only one direction. Therefore, there are two different types of dahu: the laevogyrous dahu, with shorter legs on its left side, walks around the mountain counterclockwise; the dextrogyre dahu, with the shorter legs on its right side, walks clockwise around the mountain. Respectively, the terms dahu senestrus and dahu desterus have also been used. Some sources describe a third variant, the "dead dahu" which can't walk at all. These seldom interbreed according to French lore. However, when interbred, it is believed that there are two more types of dahu. These two variations have never been seen, but are believed to exist. These variations have the leg pairs across the diagonals. This means that the dahu can have a long front right and back left leg, or a long front left leg and back right leg. It is also said that male Dahus have legs shorter on the right side and that females have shorter legs on the left side, thus making them walk in opposite directions around the mountains enabling to find each other and mate. Also, the male dahu has testicles that drag down onto the ground leaving a scent trail for members of the opposite sex to trace. Males also use the scent trails to find their next molestation victim, for dahus are known for harassing each other to assert dominance.
Hunting dahu
Like another wildlife-related practical joke, the snipe hunt, pranksters may take a victim out at night with the stated intention of catching a dahu only to abandon the victim on the mountain. Jokers may also tell a gullible subject that to catch a dahu requires two people: one with a bag, and another who is good at imitating dahu sounds. The former stands at the bottom of the slope, and the other behind a dahu. When the dahu turns around to see the source of the sound, it will lose its balance and roll down the slope to the person with the bag. Another method is to have pepper ground onto a large stone; when the dahu, while grazing, comes and sniffs the pepper, it would sneeze and knock itself out against the stone.
The rise of the dahu
The dahu is a staple of 20th-century French popular culture, known in Lorraine, in the mountainous regions of eastern France , and in French-speaking Switzerland as a theme of jokes among natives and a spoof for fooling young children. Its popularity began to soar toward the end of the 19th century. The budding tourism industry brought to the mountains wealthy city dwellers with a somewhat arrogant attitude and a paltry knowledge of the countryside. The mountaineers working as hunting guides would take advantage of the gullibility of some tourists to lure them into the "dahu hunt". The animal was touted as a rare and precious bounty, the capture thereof required waiting alone all night on a chilly slope, crouched in an uncomfortable position. In the second half of the 20th century, the supply of naive hunters had dried up, and the dahu hunt enjoyed a second life as a summer camp practical joke.
The dahu today
Since the last decades of the 20th century, the dahu is widely recognized as a fictional creature, a joke, and a metaphor for a tall tale. This legend has been widely perpetuated by Swiss foreign language teachers intending to educate their poor students who have been deprived of the knowledge of the Swiss national animal. The Alps Museum in the Bard Fort, Aosta Valley, dedicated a part of its permanent exhibition to Dahu. It has been adopted by other mountainous regions such as the Pyrenees. Recreational "dahu hunts" are sometimes organized as outdoor activities in France and Switzerland. There are dahu websites and dahu aficionados, such as Marcel Jacquat, former director, now retired, of the Natural Science Museum of La Chaux-de-Fonds in Switzerland, who wrote a monograph and opened on 1 April 1995 an exhibition devoted to the animal. On 1 April 1967, the Prefect of Haute-Savoie officially made the mountainous suburbs of the small town of Reigner a "Dahu Sanctuary" where hunting and photography are forbidden. It was a joke, according to the 1st of April tradition, April Fools' Day.