This breed is considered small; 10–13 lb (4.5–5.9 kg). At first look, the Hairless and Powderpuff varieties of Chinese Crested Dogs appear to be two different breeds, but hairlessness is an incomplete dominant trait within a single breed. The Hairless has soft, humanlike skin, as well as tufts of fur on its paws ('socks') and tail ('plume') and long, flowing hair on its head ('crest'). In addition to being an incomplete dominant gene, the 'hairless' gene has a prenatal lethal effect when homozygous. Zygotes affected with double hairless genes (1 in 4) never develop into puppies, and are reabsorbed in the womb. All Hairless Chinese Crested Dogs are therefore heterozygous.