It is described as a mountain goat-like animal with legs of differing lengths.
In French folklore, the dahu has the appearance of a deer or ibex, but with legs on one side of its body shorter than on the other side. This enables it to walk upright on the steep slopes of its mountain environment. It can only walk around the mountain in one direction. Legend says they became extinct because they were too easy to catch. There were apparently two ways to catch a dahu, either creep up behind one and say, “Dahu, dahu…” the dahu would then try to turn around ,or one had to whistle to catch its attention. When turning around, its imbalanced legs would cause it to fall down the mountain. The two longer legs now being the uphill legs, it would fall over straight away, allowing the hunters to catch it.
The dahu myth is now part of 20th century French popular culture. In
So pure fiction? I think some one got the idea from watching mountain goats and saw how they appeared to have one set of legs longer than the other from the way they stood on the mountain slopes. This then became a joke and spread. These stories have a value though, they show us how tales develop and how hoaxes are perpetuated , which is always useful when investigating phenomena.