#horn.animal_material  the material (mostly keratin) that covers the horns of ungulates and forms hooves and claws and nails
  supertype:  animal_material  material derived from animals
  substance:  keratin
  subtype:  whalebone__baleen  a horny material from the upper jaws of certain whales; used as the ribs of fans or as stays in corsets
  subtype:  tortoiseshell  the mottled horny substance of the shell of some turtles

No statement uses or specializes horn.animal_material; click here to add one.