Giraffidae

Giraffidae Temporal range: 20–0Ma PreЄ Є O S D C P T J K Pg N Early Miocene - recent
An okapi in Bristol Zoo, England
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Suborder:	Ruminantia
Infraorder:	Pecora
Superfamily:	Giraffoidea
Family:	Giraffidae Gray, 1821
Genera
see text

The Giraffidae are ruminant artiodactyl mammals that share a common ancestor with deer and bovids. This biological family, once a diverse group spread throughout Eurasia and Africa, contains only two living members, the giraffe and the okapi. Both are confined to sub-Saharan Africa: the giraffe to the open savannas, and the okapi to the dense rainforest of the Congo. The two species look very different on first sight, but share a number of common features, including long, dark-coloured tongues, lobed canine teeth, and horns covered in skin, called "ossicones".

Features

Giraffids share many common features with other ruminants. They have cloven hooves and cannon bones, much like bovids, and a complex, four-chambered stomach. They have no upper incisors or canines, replacing them with a tough, horny pad. There is an especially long diastema between the front and cheek teeth. The latter are selenodont, adapted for grinding up tough plant matter. Like most other ruminants, the dental formula for giraffids is:

Dentition
0.0.3.3
3.1.3.3

The behavior of the two living species shows little commonality, probably because of their different habitats and ecology.

Giraffe

Their closest fossil relatives include the deer-like palaeomerycids and the climacocerids, many genera of the latter having once been identified as giraffes themselves.

Fossil records indicate many other giraffids thrived between the Miocene era (around 20 million years ago) and the recent past. One major group of extinct giraffids, the sivatheres, had enormous, branching ossicones, and would have looked more like massive deer than giraffes.

Classification

Skeleton of Helladotherium, now extinct

• ORDER ARTIODACTYLA
  • Suborder Ruminantia
    • Infraorder Pecora
      • Superfamily Giraffoidea
        • Family Climacoceratidae
          • †Climacoceras
          • †Prolibytherium
        • Family Giraffidae
          • †Birgerbohlinia
          • †Bohlinia
          • †Bramatherium
          • †Decennatherium
          • Giraffa including the giraffe (the only extant), Giraffa camelopardalis
          • †Giraffokeryx
          • †Helladotherium
          • †Honanotherium
          • †Macedonitherium
          • †Mitilanotherium
          • Okapia including the okapi (the only extant), Okapia johnstoni
          • †Palaeogiraffa
          • †Paleotragus
          • †Progiraffa
          • †Propalaeomeryx
          • †Samotherium
          • †Shansitherium
          • †Sivatherium