Ungulates - mammals with hooves - account for the vast majority of large herbivores on earth. Ungulates are as diverse as they are numerous: Colin Groves and Peter Grubb, in their 2011 book Ungulate Taxonomy, recognize more than 450 distinct species of ungulates. How many appear in the following photograph? I'm sure I don't know.

For example: there are three extant species of zebra, of which we saw two on our trip.

In Maasai Mara, we saw hundreds, if not thousands, of plains zebra (equus quagga, formerly equus burchellii), also known as the common zebra or Burchell's zebra. Here is one specimen, with four red-billed oxpeckers riding on its back:

In Samburu, we saw dozens of Grévy's zebra (equus grevyi), also known as the imperial zebra. Relative to the plains zebra, Grévy's zebra - seen below - is larger, with more rounded ears. Its stripes are narrower and do not extend to its belly. (According to George, the white belly is an adaptation: in the semi-arid regions where Grévy's zebra lives, a white belly is preferred because it reflects the earth's heat rather than absorbing it.)

Grévy's zebra is an endangered species.

On the other hand, there is only one species of giraffe (giraffa camelopardalis) - but there are nine sub-species of giraffe, distinguishable by their coat patterns. Here are but two:

A reticulated giraffe, also known as a Somali giraffe, in Samburu.

And let's not even start on the antelopes...

...okay, let's.

Among biologists, the term antelope is known as a "wastebasket taxon" - a catch-all category. This particular taxon comprises all even-toed ungulates that aren't cattle, buffalo, bison, sheep or goats. (If you're thinking that "cattle" doesn't sound like a very biologically precise term, then Congratulations! You have grasped the concept of the "wastebasket taxon".)

On our safari, within this wastebasket, we found...

East African oryx (oryx beisa):

The hartebeest (alcelaphus buselaphus):

Grant's gazelle (nanger granti):

Waterbuck (kobus ellipsiprymnus):

The gerenuk (litocranius walleri), a.k.a. the Waller's gazelle, a.k.a. the giraffe-necked antelope, which can stand on its hind legs and elongate its neck to reach the tastiest parts of the acacia:

Topis (damaliscus lunatus jimela):

...and finally, the common eland (taurotragus oryx), a.k.a. the southern eland, a.k.a. the eland antelope. This shy creature is the second-largest of the antelopes; only the appropriately-named giant eland is larger:

Want to know your ungulates even better? Check out ultimateungulate.com - your guide to the world's hoofed mammals!