african black-rhinoceros collagen creases critically-endangered Diceros bicornis eating endangered folds food gray grazer grey heavy herbivore herbivorous herbivorous-browser hide hook-lipped-rhinoceros horns keratin large lattice-structured mammal megafauna odd-toed-ungulate offspring perissodactyl placid powerful rhino rhinoceros skin snout southern-white-rhinoceros square-lipped rhinoceros strong surface texture textures thick threatened tough wrinkled wrinkles zoo antler-like-horns blotched blotches brown browser camelopard coat coloring colors colouring colours creamy lines dark design feeding giraffe hair image knobs light lines long-necked long-tongued mottled nature patches pattern patterned patterns rectangular spots rothschild's giraffe ruminant strong-tongued tallest wallpaper white baringo-giraffe Camouflage creamy-lines even-toed-ungulate giraffa-camelopardalis-rothschildi irregular-patterns mane ossicones ossified-cartilage rectangular-spots rothschild's-giraffe thin-mane Ugandan-giraffe