Look at the ears!
Look at the ears!
A general rule in canids is that bigger canids kill and persecute smaller ones. In this case, black-backed jackals are killing off Cape foxes.
That would not be such a problem, because leopards keep jackal numbers in check.
This is a great example of the mesopredator release hypothesis, which holds that when larger predators are removed from an ecosystem, the smaller predators become more numerous and the species they normally kill suffer as a result of this imbalance.
Of course, the ranchers don’t want jackals either, but I guarantee you that they’d rather have jackals than the leopards.
When top level predators are taken out, all sorts of things happen to the lower trophic levels.
Increased predation by jackals on these two species of fox is just a consequence of removing leopards from the ecosystem.
One of the secrets of the dog family’s success is that they generally aren’t specialists.
Even the rodent-eating Ethiopian wolf (Canis simensis) will occasionally take a small antelope, like the common duiker or the mountain nyala.
And although there are several species of desert fox that eat large amounts of insects, none of them has specialized in eating only a single species.
However, there is a canid that lives almost exclusively on one insect species.
The species in question is the so-called “bat-eared fox” (Otocyon megalotis). 80-90 percent of its diet is the harvester termite (Hodotermes mossambicus).
We cannot say that the bat-eared fox is entirely specialized to this diet. If it cannot find harvester termites, it will eat other insects and maybe the odd lizard or small mammal.
But no other wild dog lives on such an insect-laden diet. These foxes have evolved to have more teeth than other canids– 48 versus the 42 teeth that all the other dogs have. And the teeth themselves are smaller and less designed for shearing. The selection pressures that keep most dogs with shearing carnassials have been removed from the bat-eared fox. The small teeth are well-designed fro gripping termites, even if they are not very good at cutting flesh.
After all, harvest termites aren’t particularly hard to hunt. All the fox needs to do is use its comically huge ears to locate the termites and then dig in and eat.
Compared with the complex cooperative hunting that one would observe in say a dhole or a wolf, this is pretty weak sauce.
However, bat-eared foxes do occasionally live within social groups that consist of a mated pair and one or two of the female offspring from a previous litter. These older offspring help the mated pair rear their young.
These foxes have very strong paternal parenting behavior. The male bat-eared fox regurgitates food for his offspring, and then he helps groom them and guard them while their mother forages. He also is known to play very rough with his babies. It is thought that male of this species is the parent most responsible for socializing the offspring and for preparing them for life on their own.
Now, paternal parenting behavior is very common in canids, but in no other species is the father this important to the development of the young. Typically, it is the father who take the kits out on their first termite hunt– often when they are only four weeks old!
No other male dog does this with his pups. The mother does almost nothing but nurse them.
s species has an unusually long lactation period of 14-15 weeks. Once the kits are weaned, both parents go foraging with them.
There is some debate as where bat-eared foxes fit on the canid phylogenetic tree. Early genetic assays and much of paleontology classified the bat-eared fox as a basal canid. Typical dog family phylogenetic trees have the bat-eared fox, the raccoon dog, and the Urocyon gray foxes as the most basal of all canids. Each is usually placed in its own monotypic subfamily.
However, the phylogenetic tree of Canidae that was drawn from sequencing the dog genome revealed that bat-eared foxes and raccoon dogs were more closely related to the true foxes (tribe Vulpini). The bat-eared fox is actually the most primitive of all extant Vulpini.
If we had hard time classifying the bat-eared fox, we also had a hard time naming them.
In German, it is also known by this name, which in German is “Leffelhund.”
Settlers to the Dutch colonies of South Africa saw an affinity between this fox and the jackal. Ironically, one of the bat-eared foxes worst enemies is the black-backed jackal, and otocyon are no more jackals than they are vampire squid.
The names for them in Afrikaans refer to them as jackals: bakoorjakkals (“bowl-eared jackal”) or the draaijakkals (“turning jackal”).
The latter name comes from one of the escape strategies these foxes employ when they are hunted. If a bat-eared fox thinks its being pursued, it will repeatedly double back on its tracks– turning, if you will. This behavior will confound hounds and even expert trackers, and it will allow the fox a chance to escape.
The bat-eared is a marvelous little animal. It’s unlike virtually anything else produced through the evolution of the dog family.
It has these bizarre ears and a bizarre diet to boot. It’s the only dog species that has essentially forsaken meat as major part of its diet.
But it’s also known for its cohesive family units and rather moving paternal parenting behavior.
Bat-eared foxes are in no way endangered. Their somewhat specialized diet continues to serve them well.
At some point, harvester termites might become scarce, but the bat-eared foxes can learn to eat other insects.
And there is no evidence that insects in general are becoming more scarce.
So even with this unusual diet, the bat-eared fox is doing fine.
They are certainly strange-looking little animals.
But they certain have behaviors that humans might admire.
I bet the part of this post you remember most is the father bat-eared fox taking his little four-week-old babies out on their first termite hunt.
We admire animals that are like us– even if they eat bugs!
These little bat-eared foxes are getting some milk from their mother.
When they are eventually weaned, their diet will become something very unusual among canids.
These foxes, which are found in southern and East Africa, are specialists.
Harvester termites comprise up to 90 percent of their diet.
Most other wild dogs are generalists. The Ethiopian wolf lives almost entirely on big-headed mole rats. Over 90 percent of its diet consists of that species.
But virtually all other species of canid eat more than one thing, and Ethiopian wolves will hunt other species when it is given an opportunity.
But the bat-eared fox is adapted to eating termites. It has more teeth than any other canid species, but these numerous teeth are very small and have a much reduced cutting surface than one would find in other canids.
No other canid species has specialized in this way.
If the harvester termites become extinct, the bat-eared foxes will likely follow them.
Or they might adapt to a more generalist canid diet.
But because their teeth are so different, it will be harder for them to get the same amount of nutrition from trying to hunt rodents and other small mammals.
Maybe evolution could throw them a bone, and they could re-evolve the dentition necessary for a generalist diet.
But one shouldn’t assume that it would.
Re-evolving dentition necessary for a generalist diet would have to be built upon the specialist adaptations.
And it would still likely put them at a disadvantage when it comes to other small canids.
See related post:
I don’t think the fox is fully grown, but it’s almost the same proportions from lion to fox as it is from cat to chipmunk.
It’s a cat eat dog world out there.