Which mammal of the order Pholidota is the only one to have keratin scales on its skin?
Pangolin Pangolin Pangolins or scaly anteaters are mammals of the order Pholidota (from the Greek word φολῐ́ς, "horny scale"). The one extant family, Manidae, has three genera: "Manis", which comprises four species living in Asia; "Phataginus", which comprises two species living in Africa; and "Smutsia", which comprises two species also living in Africa. These species range in size from . A number of extinct pangolin species are also known. Pangolins have large, protective keratin scales covering their skin; they are the only known mammals with this feature. They live in hollow trees or burrows, depending on the species. Pangolins are nocturnal,
Beta-keratin into the stratum corneum of the reptilian skin, providing waterproofing and the prevention of desiccation. The scales, beaks, claws and feathers of birds contain β-keratin of the avian family. Phylogenetic studies of β-keratin sequences show that feather β-keratins evolved from scale β-keratins. The scale β-keratins form the basal group in avians. Duplication and divergence events then led to claw β-keratin genes, and further recombination resulted in new feather and feather-like avian β-keratin genes. Evidence for these duplication events comes from the correlation of feather β-keratin clade structure with their genomic loci. Changes in β-keratins may have also influenced the development