DNA Sheds Light on the Only Known Battle Between Asian and African Elephant-Riding Armies

If you need proof that people have stayed the same since the days of bread and circuses at the Roman Coliseum—aside from the popularity of the NFL—go ahead and Google “hypothetical animal battles.” There’s tons of ‘em. Even if we all acknowledge that actually making animals fight each other is cruel and terrible—and we all acknowledge that, right?—there’s still a curiosity that drives people to solicit answers to the age old inquiry: Who could win in a fight between 15 chimpanzees and 15 wolves?

A team of Illinois researchers just released a study in the Journal of Heredity that remarkably combines that impulse with the military-history bug that once afflicted all old guys, and also DNA sequencing in order to figure out how an African elephant-riding Egyptian army was routed by the Indian elephant-riding Seleucidian army, in spite of the general truth that African elephants are bigger than their Indian counterparts.

After Alexander the Great’s death, his kingdom was divided among his generals. “Being generals, they spent the next three centuries fighting over the land in-between,” said Alfred Roca, lead researcher on the paper.

In 217 B.C., Ptolemy IV, the King of Egypt fought Antiochus III the Great, the King of the Seleucid kingdom that reached from modern-day Turkey to Pakistan near the town of Raphia, on what is today the border between Egypt and the Gaza Strip.

According to Polybius, a Greek historian who wrote about the battle 70 years after it happened, Ptelomy’s army, in addition to soldiers on foot and horseback, included 73 African war elephants. Antiochus’s army had fewer foot soldiers, more on horseback and 102 Asian war elephants. It’s thought to be the only battle where African elephants and Asian elephants faced off—at any rate it’s the one we know the most about.

Polybius describes what happens when war elephants face off against each other, and it sounds just about as grisley as you would expect:

The way in which these animals fight is as follows. With their tusks firmly interlocked they shove with all their might, each trying to force the other to give ground, until the one who proves strongest pushes aside the other's trunk, and then, when he has once made him turn and has him in the flank, he gores him with his tusks as a bull does with his horns.

One would think that, as the largest land animal, the African elephants would have the advantage against the Asian elephant, which incidentally is the second largest land animal. But that’s not how Polybius describes it:

Most of Ptolemy's elephants, however, declined the combat, as is the habit of African elephants; for unable to stand the smell and the trumpeting of the Indian elephants, and terrified, I suppose, also by their great size and strength, they at once turn tail and take to flight before they get near them.

Not that the Indian elephants aren’t big and intimidating, but size being relative, what’s going on here? It turns out that this misconception about the relative size of elephants was a long-standing one.

“Until well into the 19th century the ancient accounts were taken as fact by all modern natural historians and scientists and that is why Asian elephants were given the name Elephas maximus,” Neal Benjamin, an Illinois veterinary student who studies elephant taxonomy and ancient literature with Roca, said in a press release. “After the scramble for Africa by European nations, more specimens became available and it became clearer that African elephants were mostly larger than Asian elephants. At this point, speculation began about why the African elephants in the Polybius account might have been smaller.”

In 1948, one historian suggested that Ptolemy’s army was perhaps riding African forest elephants—which look like their savanna counterparts, but are much smaller, even smaller than Asian elephants—and this view became fairly widely accepted.

But historians also know where Ptolemy’s war elephants came from; they were purchased from Eritrea, which had the northern-most population of elephants in East Africa, although in the 2,000+ years since this battle, the elephant population has dwindled to just 100 elephants, one of the most isolated populations of elephants in the world. The Illinois team looked at the Eritrean elephants’ DNA.

“Sequences containing species-diagnostic nucleotide sites revealed only savanna elephant, and not forest elephant, nuclear genotypes among the elephants of Eritrea,” the study stated. “Although our results cannot completely rule out the possibility that forest elephants may have existed somewhere in Eritrea in the past, our data provide no support for this speculation.”

The odds of Ptolemy’s army riding in on a bunch of (apparently easily startled or pacifist) forest elephants seem quite slim, based on the DNA markers that the researchers looked at, including mitochondrial DNA which is passed from mother to offspring.

"In some sense, mtDNA is the ideal marker because it not only tells you what's there now, but it’s an indication of what had been there in the past because it doesn't really get replaced even when the species changes,” Roca said. “The most convincing evidence is the lack of mtDNA from forest elephants in Eritrea.”

The insight into the battle of Raphia is sort of a bonus; the real point of looking Eritrean elephant DNA is conservation. The lack of genetic diversity is expected with a small, isolated population, but it also means that the inbreeding among Eritrean elephants has left them more susceptible to disease. By sequencing their DNA and comparing it to that of other elephant populations, the researchers were able to recommend the best source of genetic diversity outside of the Eritrean elephant population—East African savanna elephants.

But by framing their study in terms of ancient elephant-on-elephant battles, it ensures that the study—otherwise just about the genetic make-up of a small, rather obscure population of elephants—gets more attention, which this article and others like it provides. Well-played, Illinois researchers. Savvier than a Ptolemaic elephant charge.