The difference in the length of such animals' legs ensures that the trunk remains horizontal, so that the bowel contents do not spill out through the orifices at either end, thus preventing an environmental disaster. This environmental principle is of central importance in the study of haggoids, i.e. the haggis and its relatives.

Animals of Type 1 are born in a valley and die on a summit.

Animals of Type 2 are born on a summit and die in a valley. There is no going back.

There are therefore creatures whose life is one unstoppable rise and others whose life is one unstoppable decline.

William Blake noted, during a spell of despondency, that we human beings start dying the moment we are born.