Though a variety of explanations have been proposed for human hairlessness, the best-supported hypothesis involves improved cooling through perspiration; while fur helps cool inactive animals, hairless skin that sweats vigorously is much better at cooling humans who generate body heat through activity.[30] Langdon, in his 1997 critique of the hypothesis, stated that the streamlining features attributed to hair follicle distribution and direction would be more reasonably achieved through changes in the shape of the skeleton and soft tissues.[4]