As I noted in an earlier post, I am skeptical that the extinct North American “cheetahs” are the root cause of the pronghorn’s speed. I am not alone in this skepticism, but my skepticism is rooted in the evasion strategy that pronghorns use. They flat-out run, whereas the antelope that are part of the true cheetah’s prey sources often use complex twisting and turning behavior to evade the swift cat. The pronghorn is a super long-distance runner, and its evasion strategy is more in keeping with a creature that was hunted by long-running dogs or perhaps the only hyena that ever existed on this continent.
I’ve been thinking a lot about cheetahs lately. A few weeks ago, I was watching an episode of Nature on PBS in which the filmmakers were putting cameras on various animals. They put some cameras on some young cheetahs, and I was somewhat surprised at a species they seemed to like to target. They were constantly harrying and harassing bat-eared foxes.
It was at that moment that two ideas I had in my head were connected. I’d been toying around with writing something on this space about the Afrikaans name for the bat-eared fox, which is “draaijakkals.” The name means “turning jackal,” and the animal got this name because when a dog would get after one, it would start twisting and turning as it ran. Now, this certainly would be the fox for sighthound enthusiasts to course.
But it really doesn’t need this skill to hunt its prey. In South Africa, it was believed they were a threat to lambs, but the truth is that 80-90 percent of their diet consists of one species of harvester termite, which don’t require much chasing.
Their running behavior is an evasion strategy, not a hunting strategy.
Why does this fox have such a gazelle-like evasion strategy? Well, I will engage in a bit of speculative zoology here:
The cheetah did it.
Cheetahs do not regularly target bat-eared foxes, but when they do, they are successful pretty often. Gus and Margaret Mills, who studied cheetahs in Kalahari, reported that cheetahs rarely hunt bat-eared foxes, but when they did, they managed to catch and kill their quarry 44.4 percent of the time. One emaciated cheetah queen, though, came to target bat-eared foxes as a major part of her diet.
Cheetahs are not migratory species, but many of their prey sources are. And during times in which ungulates can’t be hunted, some of them could very well come to rely upon bat-eared foxes as their favored prey.
Although bat-eared foxes do derive from a basal lineage of vulpine foxes, the exact species first appeared in the fossil record 800,000 years ago. And they evolvedin areas where cheetahs were present.
This little hypothesis has some problems. One of them is that cheetahs don’t often target bat-eared foxes, but we do know cheetahs will when they are unable to hunt ungulates.
But does cheetah predation on bat-eared foxes happen enough to have had that effect upon the canid’s evasion strategy?
I don’t know if we can answer that question, but it seems to me that the bat-eared foxes’ odd twisting and turning and doubling back behavior comes from cheetah predation as a selection pressure.
It is worth considering. Maybe I am way off, but I don’t know of any other canid that runs from predators in this fashion.
Or maybe it’s just another Just-So Story.