Fool’s Tigers

Aristotle is infamously wrong about stuff. He thought heavier objects fell faster than light ones, that objects had a tendency to grind to a halt without constant application of force and that matter did not consist of atoms but was infinitely divisible. These mistakes held Western science back by about two thousand years and contributed to the existence and persistence of the dark ages. It wasn’t until Newton that the first two claims were established to be incorrect and it took until Dalton in 1803 for the idea of atomic theory to be properly revived. Aristotle’s ideas in physics were basically a disaster.

That said, not all of Aristotle’s thought belongs in the dustbin. I’m personally quite keen on his ethics, for example, although not slavishly devoted to them. He conceived of virtue as being a happy medium between two vices, such as recklessness, cowardice and courage, and the happy medium as not being halfway between the two but closer to one than the other. A frequent source of friction in my life is my belief that tidiness is not only a happy medium between excessive minimalism and hoarding, but that the virtue of tidiness is closer to hoarding and messiness than it is to excessive tidiness, although I may be coming round to a different view as cognitive decline seizes my brain and I stop recognising the positive aspects of messiness.

Another surprisingly accurate area of thought Aristotle actually did excel in was biology. In fact, many of his claims previously put down as erroneous have turned out to be correct more recently. He managed to establish much of the foundations of biology and zoölogy, such as the idea of metabolism, homoeostasis and inheritance, and devised a Scala Natura, which was a hierarchical taxonomy of living beings with humans at the top and other groups further down, organised by their similarity to us, and recognised, for example, that cetaceans are mammals rather than fish. He may also have foreshadowed the theory of evolution, although this is controversial. Many details of animal behaviour turned out to be true, such as the ability of elephants to breathe by raising their trunks above the surface of water when swimming, the existence of dogfish placentæ and the camouflaging behaviour of the octopus. To some extent, Aristotle’s biology is rehabilitated.

Many of his zoölogical claims are set out in his nine-volume work ‘Τῶν περὶ τὰ ζῷα ἱστοριῶν’ – ‘The History of Animals’. There are many false factoids in these volumes, such as the idea that any two species of similar size can interbreed and produce hybrids, hence for example the idea that a giraffe is a cross between a camel and a leopard, but also many truths. From the early modern period up until the late twentieth century, many of Aristotle’s biological attestations, which were sometimes directly observed, often on the island of Lesbos where he stayed for a while, and sometimes taken as reports from fishermen and farmers, were derided and taken to be false for reasons of incredulity.

The bestiaries of the Middle Ages, which were largely allegorical in nature, took up some of his work and repeated and embellished it. Actual clear mistakes includes that female animals, including humans, have fewer teeth than males (this is true for horses incidentally), and apparently that flies have four legs, a claim also made in the Bible, but this may be a misunderstanding or mistranslation of the passages in question. The early modern period, i.e. the sixteenth century onwards, involved a backlash against his claims, and also those made in bestiaries, which led to the rejection of many things which turned out to be true.

One of the more ridiculed claims is made in Book VIII of  ‘Τῶν περὶ τὰ ζῷα ἱστοριῶν’ chapter 28, where it was stated that certain tigers living in Asia Minor and the Caucasus were completely herbivorous, mainly eating fruit. Prima facie, it seems even with modern science that this is completely impossible because tigers, being cats, are obligate carnivores. Cats cannot survive on an herbivorous diet. Their livers are nowhere near as good at detoxifying compounds as found in plants as ours are, and chocolate and xylitol, for example, are famously poisonous to them and dogs. A cat’s digestive system is short like that of other carnivores, giving them insufficient time to break down plant food, and they need fatty acids in their diet in quantity in order for their nervous systems to function effectively. This doesn’t mean a cat can’t be fed a plant-based diet, but it does mean that it would need to be specially designed and manufactured. Hence in the light of modern science, can’t Aristotle’s claim that there are herbivorous tigers be rejected out of hand? The real answer is somewhat interesting.

There was a persistent claim in mediæval bestiaries that certain tigers were indeed herbivorous. This was presented as a foreshadowing of the Biblical claim that one day the lion would eat hay like the oxen, as found in Isaiah 65:25. Although it took a while for biochemistry and other disciplines to establish exactly why, most thinkers in Western Europe ceased to take the idea seriously by the seventeenth century. However, the Arab world had also inherited Aristotle’s tradition, and not only did the belief take longer to disappear there, but in fact it hardly disappeared at all. Western science did influence the Ottoman Empire and led to a situation where belief in herbivorous tigers was considered a quaint folk belief clung to by uneducated tribes in the backwaters of the Caucasus and the like, but it never completely disappeared.

Genetic research and the ability to sequence genomes in detail and compare them between species has led to a revision of traditional Linnæan classification. For instance, there is such an animal as a hedgehog:

And also such an animal as a hedgehog tenrec:

. . . and it might easily be thought that these are just closely related species of mammal found in North Afrika (and Europe) and in Madagascar respectively. In fact, hedgehog tenrecs are as distantly related to true hedgehogs as we are to elephants. A particularly strong example of this is the previous order known as the edentates, supposed to include anteaters, aardvarks, armadillos, pangolins and sloths. Three of those are in fact closely related, but aardvarks and pangolins have nothing to do with the others or each other.

There used to be a subspecies of cat known as the Caspian tiger, who dwelt in the Caucasus, eastern Turkey and Mesopotamia, and was genetically close to the Siberian tigers living on the other side of the mountain. It was these tigers who were rumoured to be herbivorous. Nobody took the idea that they were, and in fact they were often observed eating just like other tigers and were generally the kind of beast it was wise to be wary of, rather like one might be wary of a hornet or wasp to a lesser extent, particularly if one had a severe wasp sting allergy.

There are herbivorous “carnivores”, i.e. animals related to dogs and cats as opposed to animals defined by their meat-based diets. These include the actually omnivorous coatimundi, palm civet and the red and giant pandas along with some species of bear. One rather surprising fact about giant pandas is that they used to live in Bulgaria in the Miocene epoch, and may even have evolved in Europe. There was a species of Balkan giant panda now called Agriarctos nikolovi, who died out due to the climate change caused by the Messanian Salinity Crisis, an incident where the Mediterranean Sea dried out and became a vast salt flat with ground temperatures up to 80°C due to the temporary closure of the Straits of Gibraltar. We are currently living in a temporary respite from this situation but it will have returned by five million years in our future.  Agriarctos nikolovi lived in swampy conditions in Balkan forests and was only able to eat soft plants, unlike today’s giant pandas who mainly, or possibly only, eat bamboo.

It stands to reason, or is at least superficially feasible, that if there used to be giant pandas in the Balkans and there are now giant pandas native to China, there was probably a whole strip of land between Bulgaria and the Far East which was populated by other species of panda. This particular species of panda was around two metres long but not easily able to defend itself, like today’s pandas, although it had retained largely typical carnivore dentition.

It took until the nineteenth century CE for British military campaigns such as the Crimean War and the First Anglo-Afghan War to reveal that there were Caspian tigers. The recently opened London Zoo was ripe to be stocked with captured animals, and several individuals thought to be representative of this species were brought to Britain and incarcerated in those tiny cages some of us remember as still being used in the 1970s. One of them lived out his life in these inhumane conditions, but the other specimen of these magnificent orange and black striped giant moggies, however, suffered a relatively merciful early release when she refused to eat any of the meat supplied to her and starved to death in the midst of apparent plenty. A post mortem carried out on the hapless quadruped revealed a rather startling fact: she was in fact herbivorous. She had a relatively long ileum, and later research in the twentieth century revealed that there were gut flora which produced enzymes enabling the animal to derive nutrition from plant material. It appeared to be a herbivorous tiger!

Closer examination of the animal showed that in fact the apparent “tiger” was no such thing. It was in fact an orange and black striped panda with an unusually long tail. The animal mainly ate leaves, nuts and berries, and due to her recent evolutionary history as a panda and a former carnivore, didn’t succeed in deriving much nutrition from this diet and was rather slothful and lethargic much of the time, but had somehow managed to avoid predation. It’s theorised that these “fool’s tigers” underwent evolutionary pressure to develop a tiger-like appearance which led to animals who might otherwise have preyed upon them to avoid them for fear of being eaten themselves.

This phenomenon is common in the animal kingdom. Known as Batesian mimicry, it involves an innocuous species adopting the appearance or some other prominent feature of a more hazardous species, the obvious example being the various species of hoverflies who mimic the appearance of bees and wasps, but on closer examination turn out to be flies. The animals they mimic have stripy yellow and black abdomens and appear to have a single pair of wings, but in fact wasps and bees have two pairs of wings hooked together to form a single ærofoil. Hoverflies, being true flies, have a single pair of wings in front of vestigial organs evolved from wings called “halteres” which aid balance. It appears very much that fool’s tigers underwent a similar evolutionary journey, changing their appearance from the bear-like black and white unstriped and short-tailed panda to the prominently long-tailed and fearsomely striped tiger. Moreover, although like tigers they are carnivores in a taxonomic sense and retain the dentition of their relatives, with long canines, carnassial teeth and three pairs of small incisors in each jaw, they are in fact entirely herbivorous and can’t eat meat at all. They were named Pseudopanthera dola.

The philosopher Saul Kripke has used the fool’s tiger in his influential work on the theory of names and identity ‘Naming And Necessity’. In his addendum, on page 156 of the 2001 Harvard University Press edition, he points out that an animal with the external appearance of a tiger need not be a tiger because of the existence of this species, and therefore that names are not shorthand for descriptions as had been claimed by the likes of Russell and Wittgenstein.

I have been rather remiss in finishing this post off for publication, and it seems to be around 114 days late.