Antilopine Antelopes: The Largest Gazelles

Grant's gazelle

The word "gazelle", as used in everyday English is a little vague, referring to a general concept of slim, agile, antelopes but not to anything with a precise scientific definition. Strictly speaking, however, it refers to a specific group of closely related animals, and some species that are commonly called "gazelles" strictly speaking aren't. During the 20th century, all true gazelles were placed in a single genus, Gazella, and it's this that defines the more rigid definition of what does and doesn't count. 

In more recent decades, Gazella has been split in three, with the resurrection of two 19th-century names as "new" genera. The original Gazella is widespread, including animals from both Asia and North Africa, but the other two are exclusively African. Eudorcas (literally "true antelope" in Ancient Greek) includes Thomson's gazelle of the Serengeti and its various relatives, while the remaining genus is Nanger, whose name apparently comes from a local Senegalese word for one of the species.

Antilopine Antelopes: The Gazelles of Asia

Arabian gazelles

I suspect that, on the whole, westerners associate gazelles with Africa. We think of the ones we see in wildlife documentaries, being pursued by cheetahs or leopards across the plains of the Serengeti or similar places. However, the most current theory suggests that they may have originated in Asia and various species survive on both continents today, having split apart around 2 or 3 million years ago at or shortly before, the start of the Ice Ages.

How many species that might be is still a matter of debate, and much of it centres on what's probably the first part of Asia you'd think of to look for desert-dwelling animals: the Middle East. For much of the 20th century, there were generally regarded as being two species living here, not counting one or two then thought to be extinct. And then, well, all that fell apart for reasons I wrote about on this blog back in 2013.

Antilopine Antelopes: Gazelles of North Africa

Dorcas gazelle

(Brief note: My internet connection was down for three days over the weekend, which is why this post is delayed from the usual.)

One of the things that most distinguishes gazelles from other kinds of antelope is that they are adapted to dry environments. They don't come much drier than the Sahara so it should be little surprise that gazelles are relatively common here. In fact, the dorcas gazelle (Gazella dorcas) is one of the most widespread of all gazelle species, being found right across the Sahara from the Atlantic to the Red Sea, as well as further south along the Red Sea coast in Eritrea and Djibouti and across the Sinai into extreme southern Israel. In the north, it's largely restricted to the eastern parts of the Mediterranean coast, being absent from northern Algeria, Morocco, and Tunisia.

Antilopine Antelopes: Tommy's Gazelle and Relatives

Thomson's gazelle

You probably don't need to live in Africa to be aware that there are a great many different kinds of antelope. (A couple of years ago I came across an online picture quiz of "can you name these African animals?" Over half of them were antelopes.) It's hard to say which of these are the most familiar to the general public, because quite a few of them probably are, at least in general terms. But one subtype of antelope that people will at least recognise are the gazelles.

Gazelles are smallish, fleet-footed animals; the word comes from the Arabic ḡhazāl, which literally means something like "slim/agile creature". Gazelles are widespread, perhaps surprisingly so, and there are many different species. Of these, the one that may be the most familiar to people outside of Africa is Thomson's gazelle (Eudorcas thomsonii) for the simple reason that it's the one that lives in the Serengeti and therefore gets into a lot of wildlife documentaries. Mostly getting eaten by big cats, to be sure, but it's a start.

Pliocene (Pt 3): Of Gazelles and Three-toed Horses

Hipparion

The Zanclean Flood may have been a catastrophe of epic proportions, but, so long as you were above where the flood waters eventually stopped, Europe at the dawn of the Pliocene was a fairly pleasant place. The weather was warmer than today, and, apparently wetter too, which might not be what time-travelling tourists would be looking for, but was certainly good news for the plants that were actually there. Where places like Spain, Italy, and Greece are today dominated by... well... "Mediterranean" scrubland, back then they would have been considerably greener. And what's good for plants is good for herbivores.

Especially when it comes to cloven-hoofed animals, many of these would have been animals that would have been, at least in general terms, familiar to us. Not necessarily familiar to us from Europe, though, since, in addition to pigs, bovines, and deer, there were also a number of antelopes. These were mostly members of the gazelle subfamily, although there were others, including some, for example, related to the modern sable antelope. The gazelles included Hispanodorcas, a small and slender antelope with slightly twisting horns, with fossils found in southern Spain. However, some were even closer to the gazelles of today, to the point that, if, like most people, you'd be pressed to tell the difference between a Dorcas gazelle and a Speke's gazelle today (or at least, to know which one was which), you'd probably not have identified these as anything different, either - although at least some of them were smaller than any living species, which might have helped.

One Gazelle or Two?

Mountain gazelle (probably)

According to the International Union for the Conservation of Nature, there are sixteen living species of gazelle. However, as I've mentioned before, counting species isn't always as simple as we might like to think, because the lines between them often blur. Are those two, similar-looking, animals separate species, or just two subspecies of the same thing? And how would we know?

You might suppose that the answer is something along the lines of 'do they cross-breed to produce fertile offspring or not?' Horses and donkeys are different species, you might think, because, while they can interbreed, the result is a sterile mule. Similarly, tigers and lions can also cross-breed, but the results are usually infertile. (Actually, fertile mules and "ligers" do exist, but they seem to be rare). If they don't cross-breed at all, of course, the answer is even simpler. So, take the two gazelles you're wondering about, mate them, and see what happens. Right?

Well, not really. For one thing, that's much easier said than done, especially if one of the possible species is endangered. It's hard enough getting pandas to mate with other pandas to be sure that mere lack of mating proves anything at all. Not only that, but there are, believe it or not, a number of cases where animals that are clearly different species can, indeed, interbreed to produce fertile offspring. Polar bears and grizzly bears, for instance, to give one example becoming more common of late.