There's a traditional Scottish answer to the question "What is a haggis?" This answer suggests that a haggis is a small four legged creature found in the Highlands of Scotland. The legs on one side of the creature are smaller than those on the other, which means that it can run around the side of hills easily at a level altitude: but it does mean that the haggis can easily be caught by running round the hill in the opposite direction, for the creature cannot turn round to escape. If it did so the difference in the length of its legs would cause it to lose stability and roll downhill, with fatal consequences.
One theory suggests that there are actually two species of haggis. One has longer left legs, the other longer right legs: so while one goes clockwise around hills the other goes anticlockwise around them. The two species coexist peacefully, but cannot interbreed. For a male to turn around and attempt to mate with a female of the "opposite" species would cause it to lose stability and roll downhill, with fatal consequences. The result of this over time has been to cause the difference between leg lengths in both breeds to become more marked.
Haggis are hunted in the wild and the end result is the well known sausage-like food that we all know and love. This Australian news report from 2003 quoted a survey of 1,000 Americans in which almost one in four US visitors to Scotland thought it was possible to hunt and catch wild haggis, and one in three believed the animal was real. (We're not mocking Americans: we thought roadrunners were found only in cartoons until our first visit to West Texas).
The bad news is that the haggis is not actually an animal. The description of its ingredients and preparation does little to enhance the enjoyment of this dish, and that is possibly why the myth of the wild haggis has so often been used to mask the reality: of the heart, lungs and liver of a sheep being cooked with other ingredients inside its stomach.
Interestingly enough, there is an equivalent mythical creature in Canada. This is the sidehill gouger, a resident of the Rocky Mountains of British Columbia. Apart from the difference in name and habitat, in all other respects, the sidehill gouger is almost identical to the wild haggis...