Our Ancestors

When should a story begin? If it’s a biography, common practice seems to be to recount the lives of the subject’s parents, although one might also talk about a more distant background. If I think about my own life history, it feels like a mistake to focus too much on background because it can easily drift into nationalism and racism. Many online discussions about genome analysis undertaken on White people seem to be embarrassed about recent Black ancestry and tend to be couched in terms of them being errors due to small amounts of data, which is really sad. On the other hand, it’s also possible for a White person in particular to appropriate swathes of Black or other Disneyfied ethnic identity for themselves for some kind of cringeworthy cool factor. Since my own ancestry is substantially Scottish, I could easily slot myself into tartanry. This kitschiness is very much to the fore and has been going on for two centuries now. Wikipedia describes it as “twee, distorted imagery based on ethnic stereotypes”. Two images of this in particular come to mind, both rather similar. One is of a tourist picking up a soft toy of a tartan mouse in Inverness and saying  ,,Eine schottische Maus”, and the other is of a plethora of tartan Nessie plushies in a Loch Ness visitor’s centre gift shop. On the one hand, it’s quite embarrassing, but on the other one can understand the need to turn a somewhat honest penny in a remote location with few economic opportunities, and I imagine the same love-hate relationship with tourism I used to experience in Canterbury would be reproduced there. You need the tourists but they can be almost immediately tiresome.

In the case of human ancestry, we are all currently the product of at least two parents, who are in turn the product of two parents and so on back to a point where we appear to have more ancestors than the human population of the planet at the time. In fact you probably don’t even need to go back that far to experience that quandary, as people didn’t used to move around as much as many of us do nowadays. Many of my ancestors would probably have ended up marrying someone in the next village, or even the same village, and you can easily get back to the point where your family tree didn’t seem to have branches. This applied as much in West Afrika as it did in Argyll, although people did become displaced from both locations by events such as the Atlantic and Barbary Slave Trades, the Highland Clearances and the Famines. These mixtures have brought the common ancestors of all humans forward by millennia, such that it’s now estimated that our most recent common ancestor lived in the late Bronze Age, which when one considers how isolated certain groups are, such as in Papua or the Amazon, is quite counter-intuitive, but this reflects what has happened in recent centuries rather than further back.

As one ascends the global family tree, the generations become increasingly diagonal. Because most couples have at least two children survive to have children of their own, their age differences add up and start to skew the ages of people who, for us descendants, appear to be in the same generation. An extreme case of this might be a mother who has a child at twenty and another at forty, which is effectively a whole generation apart. In that case only two generations are needed for people in the same family to have a big enough age difference to be grandchild and grandparent, though not in practice of course. Even a year’s difference can achieve this within twenty generations. This also means that when one considers one’s ancestry, the range of possible dates of birth of unknown ancestors widens the further up you go. What would eventually happen, with perfect knowledge of the world’s population, is a family tree with multiple instances of the same individual in many places and different generations relative to oneself. The consequence of all this is that we are all part of the same human race.

This makes a lot of sense when considering evolution. It’s easy to imagine evolution as a sudden change in the population, and certainly point mutations do lead to this, but in fact what seems to make more sense is for a trait to begin in a certain individual and then spread across the species, and another trait to begin elsewhere and similarly spread, until you end up with a situation where either both traits, and of course many others, have spread throughout the population, leading to it having become a new species, or only some of them have, leading to either a ring species or the separation of the population into two or more such species. For solely sexually reproducing species, there cannot be a single founder of a new species, so for us, going way back into the past, it has always been a question of entire populations evolving together into new species.

A few days ago, I communicated poorly with someone by saying that our ancestors arose in North America, because they thought I meant hominids, the family including orang-utan, humans, gorillas, bonobos and chimpanzees, had arisen there. This is by no means the case of course, although there used to be a school of racialist anthropologists who believed in polygenesis: that the ancestors of surviving humans were already several different species. This would make humanity a grade rather than a clade – a group of organisms with the same kind of organisation in terms of anatomy and physiology which are, however, not descended from a common ancestor with those characteristics. These are seen a lot in biology. For instance, reptiles, when considered as a group of scaly air-breathing vertebrates whose bodies are at the same temperature as their surroundings when at rest, constitute a grade if some of the extinct “mammal-like reptiles” are included and birds excluded. Likewise, the mammal-like forms themselves consisted of several parallel lines developing the same kinds of characteristics but not from a common ancestor, and even hominids have done this. There used to be some confusion around a species of ape who had a number of particularly humanoid characteristics living in Europe before the first of our immediate ancestors got there, suggesting that we had evolved in Europe. The fact is that related species are wont to develop similar traits due to having similar genes and sometimes being in similar ecological niches.

But I actually meant omomyids. I think I’ve mentioned these before in this blog, so I won’t go into super depth on this, but back in the Eocene, 56-34 million years ago, primates were chiefly found in North America, and were of two main types: the adapids and the omomyids. Adapids were more lemur-like but less specialised, lacking the comb-like incisors and grooming claws found in many of their descendants. Both groups are themselves descended from the plesiadapiformes of the Palæocene, several million years previously, who looked like this:

By Nobu Tamura (http://spinops.blogspot.com) – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19460197

Thus when I said “our ancestors”, I was referring to early primates, not hominids. It may be a little surprising that primates first appeared in North America, a continent from which non-human primates are almost absent (there are spider and howler monkeys in Mexico), but this distribution change is not unusual. Camels first evolved in North America around the same time as omomyids, but are now found on every continent except North America and Antarctica, although the Australian population is feral. Likewise, the earliest horses evolved in North America, spread to South America after the continents joined, then both American horse genera became extinct at the end of the last Ice Age, leaving them in Afro-Eurasia alone. This may, incidentally, have had huge consequences for human history as the domestication of the horse and the absence of exploitable beasts of burden in the Americas seems to have led to a major split in the types of culture which arose in those continents compared to Eurasia. There is in fact something of a pattern here, of particular mammalian clades evolving in North America, spreading elsewhere and then becoming extinct in the continent on which they originated. At the time, Earth looked roughly like this:

By Ron Blakey – https://www.thearmchairexplorer.com/geology/paleogene-period, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=83234895

I chose a particular cut-off point here in a sense, because clearly forms ancestral to the primates would not initially have been native to North America, but the point was to contrast them with possible prehistoric Antarctic mammals. The Eocene was an extremely hot period, more so than any time during the reign of the dinosaurs, and consequently Antarctica was by no means snow-bound or ice-covered. The question was asked of whether there had ever been indigenous Antarcticans, to which the answer is not only “no”, but also that there haven’t even been indigenous Antarctican primates. One of the big divisions among mammaliforms is the Boreoeutheria versus the Gondwanatheria. As the name suggests, Boreotheria first evolved in the north, and share the primitive feature of males having scrota. They evolved about four million years before the Chicxulub Impactor arrived and were ancestral to the Euarchontoglires, a superorder including colugos, tupaias, rodents, lagomorphs and primates, as well as the Laurasiatheria, including fissipedal carnivores, seals, pangolins, odd- and even-toed ungulates, whales, hedgehogs and their kin, and bats. By contrast, the Gondwanatheria were native to the southern hemisphere, including Antarctica, may not even have been true mammals as such, and if they were, may have been a separate group of mammals and arguably the most successful and definitely the most durable, group, the multituberculates, mentioned before on here. Another southern group of mammals hard to place in relation to other placentals is the Xenarthra, who include sloths, armadillos and anteaters. There are also the Afrotheria, which include aardvarks, elephant shrews, some other shrew-like mammals, hyraxes, elephants, dugongs and manatees etc, and various extinct groups. Besides all these, there are of course the marsupials and monotremes (surviving egg-laying mammals). Hence Antarctica did seem to have marsupials and possibly some other mammals native to the southern hemisphere.

Back to primates. Omomyids and adapids had separate fates. It’s common for creationists to ridicule the established scientific paradigm by stating that the claim is that we evolved from monkeys. This is “not even wrong”, as the phrase has it. The earliest simians were the omomyids. They were somewhat tarsier-like, and although they began in North America, they spread into Eurasia. Tarsiers themselves are somewhat specialised, being nocturnal and having large eyes which are impossible to move by themselves, so their necks turn round almost all the way, which has led to them being perceived as spooky. They’re also kind of carnivorous, but like all simians (and no other primates) they need vitamin C in their diet, so I presume they must also eat fruit or some other good source. Omomyids generally had smaller eyes, were sometimes diurnal and had less flexible necks. Tarsiers have basically been the same for 45 million years now, so if you want a rough approximation of what our ancestors looked like, they wouldn’t be far off.

All monkeys, Old World and New, are descended from omomyids. The peculiar claim that apes are not monkeys is a bit dubious because cladism insists on creating groups consisting of all descendants of a common ancestor, so in that sense we are still monkeys. We’re also apes, and apes are monkeys. This is a little awkward, because of the sloppy use of terminology that tends to call non-human apes monkeys. Technically that’s correct, but they’re tailless monkeys with torsos wider than they are thick. Another issue is with the racist use of the words to imply inferiority, meaning that although biologically we’re monkeys and of course also apes, it may also have offensive connotations. One answer might be to reclaim these terms, but as the world’s Whitest woman I can’t really go around saying I’m doing that for their sake, any more than I can spell “Afrika” with a C in spite of the fact that I have my doubts about the rationale of spelling it with a K.

The question arises of what happened between the omomyids and the emergence of hominids. This would be the Oligocene. In the Miocene it’s well-established that there was a great variety of different kinds of apes and it’s therefore difficult to trace human lineage through that thicket of similar forms. Before that, however, was the Oligocene. A significant animal from this time is Ægyptopithecus zeuxis:

By Nobu Tamura (http://spinops.blogspot.com) – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=19459879

This primate lived before the ancestors of Old World monkeys and the ancestors of apes separated, around thirty million years ago. Before this, there was an Old World primate called Oligopithecus who was more like a marmoset or tamarin than today’s Old World monkeys, and this raises the issue of how they got there. The split occurred about forty million years ago, which is in the Eocene, and their arrival in South America is controversial. Although there were primates in North America at the time, which would’ve meant convergent evolution with Old World monkeys to some extent, it’s more likely that they travelled over the Atlantic on rafts of vegetation, bearing in mind that at that time the ocean was narrower and the rainforests in Afrika still existed further north. Hence sadly, monkeys did not evolve twice. If they had, it would make the idea of humanoid aliens slightly more plausible. The New World monkeys themselves began to diverge from each other around 27 million years ago and now comprise five families. Although the smaller marmosets might be thought of as having evolved from larger monkeys to occupy the vacant prosimian niches in the Amazon, in the light of the likes of Oligopithecus it looks more like they were the more primitive forms and the reason they’re more prosimian in size is that they’re genetically closer to them, although this is just my guess. It does make sense that it would’ve been easier for smaller primates to survive being swept across the ocean, but there were other primates which initially made a living there but soon died out, such as the Afro-Arabian-Asian parapithecoids, who were very monkey-like.

Primates used to be a lot more widespread than they are today. There were European native primates such as Dryopithecines, who could’ve been closer to Afrikan apes, orangutan or perhaps equally related to both. They’re quite neat, as they’re apes who dominated Europe before humans reached here. They were roughly bonobo-sized and ate fruits and leaves. Later on, they may have built up fat reserves in the summer to tide themselves through the winter.

As for our immediate hominin ancestors, I should hold my hands up here and confess to being an adherent of the aquatic ape hypothesis. The standard narrative is that some apes became more humanoid during the drying period of the late Miocene and the Pliocene, being forced to survive on the Afrikan savannah. This is not what I believe. In order to explain why this could not have happened, I need to talk about endogenous retroviruses. These are stretches of genomes which used to be viruses, which have transcribed their genomes into those of other organisms. At some point in the Pliocene, baboons started to shed a virus of this type which infected all other primates in Afrika. No Asian or South American primates have this area of genome, and all Afrikan primates do have it. Humans do not have it, although up to eight percent of our genomes are made up of retroviral code. This is from before the appearance of genus Homo. It appears to support an Asian origin for our ancestors, but it’s equally compatible with them having been isolated on an island off the Afrikan coast. The oldest stone tools are found in Ethiopia and seem to have spread south. There are also a number of adaptations in humans which suggest we spent a lot of time in the water, such as:

• Near-hairlessness.
• Insulation from fat deposits, including floating breasts more accessible to young in the water, along with long scalp hair affording protection from the Sun and a handhold for babies.
• A hymen, protecting the reproductive system from sand.
• The presence of a diving reflex, where metabolism and heart rate slow when immersed in water.
• Breath control.
• Face to face lovemaking, found mainly in marine mammals.
• Downward-facing nostrils.
• Erect bipedalism.

I’m not being thorough here. This is just a selection of adaptations which suggest we had an aquatic phase. However, this doesn’t mean we lived in the water like dolphins. It’s more like we lived on the beach and escaped into the water from potential predators, kind of like we were semi-mermaids. It’s also possible that elephants went through a similar phase, as they still have a lot to do with water. Moreover, early stone tools were made from pebbles, as found on beaches. Proboscis monkeys also have similar adaptations, such as their noses, and spend some time in water.

I think that’s all I really want to say today. It’s a bit spotty, but I’ve tried to highlight some of the less well-known bits of the history of primates. There’s a lot of other stuff, such as the orang-utan relatives who lived in the Himalayas and the recently extinct northern Chinese gibbon species, but this will probably do for now.

The Veganism Of Prehistory

By Nobu Tamura (http://spinops.blogspot.com) – Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=19459226

Every organism is a creature of its time and humans are no exception. Nor are individuals. However, people can be anachronistic and so can species. Living fossils, for example, and Lazarus taxa, such as the allocaudata, an order of salamander-like amphibians who are, however, not closely related to them and seemed to vanish at the Chicxulub Impact but then appeared again millions of years later. However, these are exceptions, and on the whole we don’t do things out of time. For instance, the issue of Jacobitism doesn’t now seem like the kind of thing anyone would take up in earnest in this country, although the Royal Stuart Society and Royalist League, and the Richard III Society, do seem to have elements of an anachronistic nature. It’s hard to see their wider relevance nowadays.

This applies to diet in a couple of ways. There’s the kind of diet we and our ancestors would habitually eat, and there’s the kind of diet we could eat, in the past. In the West, vegetarians used to be called “Pythagoreans”, after the vegetarianism of the followers of Pythagoras, who lived (if he was a real historical figure) twenty-six centuries ago. Carol J Adams’ 1990 work ‘The Sexual Politics Of Meat’ points the way to a gender-based understanding of attitudes towards diet which may have skewed perceptions of history and evolution in a carnist direction which are worth bearing in mind, but I have to leave this to one side because of the focus, or lack thereof, of this blog. Incidentally, I can’t really mention Adams’ book without commenting on a statement she made in it which has always struck me as peculiar. She says there must be some significance in the fact that “so many feminists are vegetarian”, when in fact it’s always seemed odd how few feminists are vegetarian.

There are really two ways in which this can be considered: the diet of our ancestors and the possibility of making that choice in the past. Human history itself is the realistic application of these two, but it’s also fun and informative to take it back further to consider how we could’ve eaten if we hopped in a time machine and went back, say, to the early days of the dinosaurs or beyond.

Adams makes the point that through much of the history of Christendom, most people, and those in religious orders in particular, would’ve spent much of their time eating a practically vegetarian diet, because of the lack of food generally and also due to holidays which required partial fasting and the avoidance of meat. Dairy production was also far less efficient and it would’ve been difficult to transport dairy into cities without it going off. It also didn’t have the later veneer of being a healthy food which it later acquired. In the modal Western diet, dairy stands out as the oddity rather than meat or vegetables. Egg consumption was also for a long time not accompanied by the consumption of chicken, who I think weren’t considered edible although I couldn’t swear to that. On the other hand, the perception of fruit and vegetables was quite negative compared to meat, because they were considered cold in humoral terms. Culpeper, for example, expresses surprise that cucumbers are not poisonous because they’re so cool. The idea was that they should be eaten only in moderation and that meat should be the staple fare, along with bread. I’m obviously talking about Europe here. There’s also the issue of scurvy, which used to be much more loosely defined than it is today. Although people were aware of the value of Citrus fruit in preventing it, as its understood now, from Mediæval times onward, they thought this was connected to the acidity of the fruit as such rather than any more subtle principle within it, which is why they went for limes. It also meant that any kind of acid food would be latched onto as a cure or preventive. The actual experiment which established the use of Citrus scientifically occurred in the early modern era and was a good example of an early scientific experiment, which incidentally also showed the value of cider as a source of vitamin C. By that time, however, scurvy was mainly a mariners’ problem because potatoes were effective in warding it off onshore. This probably marks the start of the idea that vegetables and fruit could be healthy, although Pythagoras had thought of them in these terms millennia earlier. It isn’t clear to me whether this is primarily European, but there seem to have been no recorded herbivorous cultures. The closest are probably the Jains, but they preferred dairy to root vegetables, which they forbade. More recently, RastafarIans have tendencies towards plant-based diets but it doesn’t actually seem very common among them so far as I can tell.

As I’ve said, it’s the consumption of dairy which is the oddity, not that of meat or plants. This seems to have appeared among nomadic pastoralists who followed bovines, letting their blood and squeezing milk from their udders. For Europeans, in conditions of poor sunlight, it’s difficult for the skin to synthesise vitamin D₃ and therefore we retained the ability to digest milk as adults, as have some other populations. Egg-eating makes more sense because taking eggs from birds’ nests is a form of foraging. There is a question regarding how much of a contribution meat and plants make to a hunter-gatherer diet, and if there’s a gender-based division of labour there. This is where we get into the question of whether vegetarianism is “natural”, bearing in mind that that’s a dodgy concept in the first place. My position on this is that the human body is adapted for an omnivorous diet, but that this has two consequences: it means we have great flexibility in what we eat, to the extent that we can eliminate animal products entirely, bearing in mind that we are also capable of discovering and remedying any problems with that; and, in the case of mammals, most omnivores mainly eat plants with a few animals. In fact even some herbivores eat animals and it’s quite rare for a mammal to be truly herbivorous. Deer, for example, eat chicks.

There are a couple of arguments for the idea that meat-eating was a factor in the growth of the human brain and sophistication of our culture. These come down to two factors: nicotinamide (vitamin B₃) and fat. Considering the first, nicotinamide is vital in the Krebs Cycle, which is the way oxygen-breathers release most of their energy from glucose and is therefore central to ærobic life. To me, nicotinamide is a vitamin found in seeds, nuts, pulses and grains, like many other micronutrients. The final category is the most difficult to obtain in quantity as a forager, and this is what would be missing from a hunter-gatherer diet. The growth of the human brain from infancy on is very energy-intensive, taking up three to four fifths of the energy from food, and since the Krebs cycle depends so heavily on nicotinamide, a good source of that is required, which would be offal. The standard narrative also includes the idea that hunting involves strategy and competition with other predators and therefore selects for intelligence. However, this ignores the fact that gorillas have human-like intelligence and are largely herbivorous, and the frugivorous orang utan are also. There is only a very slight difference in intelligence between us, and although a slight advantage can add up over millions of years, have we been separate from other the Afrikan apes for long enough to make that big a difference?

The other theory involves fat, taken from the bones of animal carcasses and a major component of the central nervous system. Meat consumption itself relies on cooking because the energy taken in chewing raw meat doesn’t lead to a break-even situation regarding energy extraction, but scavenging bones is easier. Bones are also easier to remove from exposed sites where potential predators might lurk or themselves be attempting to scavenge. The savannah theory sees us as changing our diet about 3.7 million years ago when large open spaces became available to us. Bones could be broken open using stones, and sharpened stones would make that easier. However, this is another area influenced by gender politics because it’s based on what the men were doing, at least as projected into the past from recent years in the West. Elaine Morgan’s aquatic theory, which takes women into account more, sees us as living on the shores of the Horn of Afrika and eating molluscs and fish, venturing into the water to escape threats on land and escaping from the harsh environment of the Sudan and Sahel, Sahara Pump Theory notwithstanding, because to an animal adapted to rainforest conditions this would still be inhospitable.

It’s difficult to discuss human evolution and diet without getting bogged down in matters of gender. This would normally be fine, but because I’m quite strict with myself separating the subject matters of my different blogs, I can’t really do that here. Therefore I’m just going to say that regardless of how we evolved and the extent to which we depended on animal products, it’s no longer necessary to do so, in the same way as it’s no longer necessary to wear animal skins, hunt for food or make stone tools.

There may be a carnist bias in how palæontologists view human evolution. For instance, I’ve seen Australopithecus boisei described as a “vegetarian dead end”. Apparently this is now known as Paranthropus boisei, or rather this is the more robust of the two, and the genus Paranthropus may be synonymous with Australopithecus. They lack tooth fractures, suggesting that they ate fairly soft food, and the levels of strontium were higher in their milk teeth, suggesting that the children ate tubers more than the adults. Strontium isotopes also indicate that the women left their birthplaces but the men stayed local. The problem with working out how they lived is that they were savannah apes, but not as specialised in that kind of niche as our own species, and there are now no other savannah apes. It is known, however, that they ate termites. They were able to eat the dried up plant food during a long dry season, unlike their contemporaries Homo habilis. Although these did eat meat, they were more threatened by climatic extremes. However, the success of Homo as opposed to the other, or other two, genera, may rely more on their generalism and versatility than their diet. Also, there are other herbivorous species on this planet with human-like intelligence, such as elephants and parrots.

During the Miocene, the period preceding the emergence of identifiably human apes in the Pliocene, there was much more diversity and great apes other than the yet-to-evolve humans were found in Eurasia, including Europe, which by that point did exist but the North European Plain was underwater and the Mediterranean was open to the Caspian with a couple of inlets in Mitteleuropa. Diets can be reconstructed by patterns of wear on their teeth, and they seem to have begun eating hard-shelled food such as nuts and fruits and later evolved to add soft fruits. They then died out as subtropical vegetation was replaced by deciduous trees. At some point during the Miocene, between eighteen and thirteen million years ago, the Afrikan and Asian great apes diverged. Ramapithecus and Kenyapithecus are two very similar Miocene great apes, one found in Asia and the other in India, which may be the common ancestor of all surviving great apes. These had thicker enamel, meaning that they probably ate tougher food, once again vegetation with high cellulose and lignin content. A famous simian from the Oligocene, dating from before the apes and Old World monkeys diverged, is Ægyptopithecus, found in Egypt and dating to around thirty million years ago, ate fruit. There are other simians from this epoch too. They arose from tarsier-like animals found in the Northern Hemisphere referred to as omomyids, whose earliest forms are fifty-six million years old. Tarsiers are carnivorous, or more strictly speaking insectivorous, not eating much in the way of plant matter, but compared to them omomyids teeth suggest they also ate fruit because they were blunter than the more recent animals. They were all less than half a kilo in size. Accompanying the omomyids in the Northern Hemisphere, including North America like them, were the lemur-like adapids, who lacked the combs found in lemur dentition, and whose mandibular musculature suggests they ate leaves. Going further back still, there was a split between the ancestors of the colugo and the primates 80 million years ago in the late Cretaceous, and about five million years before that we have ancestors in common with rabbits, rodents and tree shrews. Most of these are primarily herbivorous, but the tree shrews are omnivorous. Before that, our ancestors are shared with a much wider range of placental mammals, many of whom are now carnivorous, diverging 107 million years ago, and so forth back into the Mesozoic. But you have to go back a long way before you find even insectivorous ancestors, let alone ones usually seen as carnivores, i.e. predatory animals who hunt, bring down and eat live animals around their own size.

All this, though, is a mere appeal to nature. Just because none of our ancestors were biologically committed to eating meat evolutionarily doesn’t in itself constitute an argument for not eating it. Also, if you push back far enough into the Jurassic, things change quite drastically in terms of what our ancestors could possibly have eaten, because the slow drift of plant evolution comes into play. Changes in animal life are often provoked by changes in plant life, because ultimately that is what we all depend upon. Plant life had to exist on land in order for herbivores or carnivores to live here long-term, the alternative being fungi, which were here for longer but don’t seem to have been accompanied by animals. The first herbivorous dinosaurs could not have existed without ferns and cycads. Pollinating insects and flowering plants co-evolved, apart from the wind pollinated ones. And primates also, and their ancestors, needed soft fruit to exist and evolved to exploit the new niche of frugivore. The question then arises of what we as human beings would be able to find to eat if we travelled back in time.

In order to eat a modern Western diet, we would need gluten. Even if not, cereals are likely to form a large part of our diet, and that applies to most people not following palæo across the planet. For that to be possible, grass must exist. Grass has a somewhat peculiar history because although it evolved a long time ago, for quite a long interval, it was just one plant among many. There were grasses in varied meadows, so to speak, but no grassland. Wheat fields, rice paddies and the like are really just artificial grasslands. These didn’t become common until the Neogene, i.e. the Miocene onward. Our ancestors didn’t appear on them until the Pliocene, after the world had become dry enough for them to spread. Grass acts as a food source for us in various ways. We have rice, barley, wheat, rye, maize and millet, whose seeds we eat, but there’s also sugar cane, bamboo shoots, bamboo flowers and the simple practice of picking up a grass stalk and sucking it, and more generally but applicable to grass is the production of leafu, which is a kind of strained, compressed curd made from almost any edible leaves. I used to eat blades of grass as a child and it cut the inside of my mouth quite painfully. Any sensible person needn’t be told that grass is too fibrous to be chewed safely, and I presume the species who eat it on a regular basis either have tough mouths or eat the softer bits. A large portion of the meat humans eat is specifically from grass of course, an ecological relationship which has largely arisen in the Neogene. In a nutshell, grass is pivotal to life as we recognise it today. Nonetheless, it isn’t really feasible to avail oneself of cereal grains without farming in the quantities required to make flour and the like, and everything that leads to.

I first came across the palæo diet before it had that name, I’m guessing in the later 1980s, from the. It seems to make sense at first, in that we evolved without access to milk from other species as adults along with processed food and cereals in bulk. However, much of the palæolithic diet, and of course there wasn’t just one, is unknown, and the original idea for the palæo diet was based on a few hunter-gatherer communities in marginal environments such as the Kalahari and the Arctic. These may not be typical of what we used to eat because we weren’t living in such mean circumstances. There are reasons why hunter-gatherers who still survive today live where they do. It would also be necessary to wildcraft food from non-cultivated varieties. I don’t know if they pursue this, but most brassica, for example, is ruled out because it’s so far from its wild states. Agriculture has also existed for about ten millennia now, and this will have influenced our evolution to some extent. As mentioned before, we are also omnivores – our diets are varied and we are able to eat a wide variety of foods without harm. That said, I do believe dairy and some processed food is unhealthy, and also much farmed muscle meat. This is now edging into herbalism territory, so I’ll step back from this.

Attempting to make a moral choice regarding diet, or perhaps one based on cultural preferences, shouldn’t meet with the kind of stonewalling and excuses it often does. If there’s a deeply held principle involved, the answer is not to abandon it but to seek a way in which it can be done safely and healthily. It’s very common for people to object to a plant-based diet by saying there are people it won’t work for because of their health or perhaps that it won’t work for anyone, but if that’s true, it actually means there’s a moral imperative to pursue research or take steps so that it does become an option. If there were genuine vampires who could only survive on blood drunk from a living human subject and this was considered an unethical practice, measures would need to be taken to ensure that vampires could continue healthily without violating other people’s rights. For example, it would be worth investigating why only a living subject was suitable and trying to duplicate those conditions, or looking for donors willing to undergo the process. It wouldn’t be acceptable just to consider vampires a basket case and abandon them to their fate. Likewise with veganism. It’s always a question of how to facilitate it, never whether one should do it at all for any particular group. The same applies to halal and kashrut.

Fruitarianism would probably fare rather better, particularly considering that climates were more amenable to soft fruit back in the day, and of course it is what our ancestors were actually doing at the time. There are B vitamins missing or almost absent from soft fruit, but fruitarianism isn’t just eating what we conventionally think of as fruit but any fruiting body of a flowering plant, and with that broader scope, which includes nuts, and pulses unless it’s raw food veganism which would restrict pulses to peanuts, it’s a lot more balanced. The B₁₂ question is easily resolved, as gorillas also get deficient when captured and only given washed food – it’s simply in the environment in bacteria, though perhaps not in sufficient amounts. In plants today, although there are similar compounds to cyanocobalamin, there are no exact equivalents. That, however, doesn’t mean there aren’t extinct plants which did have that exact compound, although this is clearly speculation. Vitamin D, though it can be synthesised in the skin, is also present in an Afrikan plant in sufficient quantities for ungulates to overdose on it. It’s also found in fungi when they’re exposed to sunlight, and perhaps the key in general here is to look to fungi as a source of nutrition.

The question of scurvy arises here, but pine needles are high in vitamin C and conifers have been around a lot longer than flowering plants, dating back to the Carboniferous. What I don’t know is whether conifers generally are high in vitamin C. Before the evolution of flowering plants, a possible source of carbohydrates would be cycads, which are however also high in toxins which are irritant and damage the liver, and would therefore need to be leached out. It seems that the relatioships which now exist between animals and flowering plants weren’t present between gymnosperms and their contemporaries before their appearance. This has the consequence that the further back in time you go, the harder it gets to acquire the foods humans would need to survive, and whereas this is partly because the plants in question had yet to evolve, it also underlines the significance of the web of life within which we live. We can’t be separated from our environment. The very fact that we’re susceptible to scurvy is only because our ancestors spent so long eating fruit that we lost the ability to make our own. There is a pseudo-gene still there which is found elsewhere in mammals as a functional gene, but it doesn’t work in humans.

Carnists would to some extent find it easier than vegans, because meat would be available aplenty, as would insects, and this goes back a long way. However, there is still hope for a time-travelling vegan in the Palæozoic. Seaweed is a good source of minerals in particular, but also other nutrients, although it’s also notable that if you go back far enough there seems to be less energy-rich food, which may be linked to the absence of “warm-blooded” animals. What is available, apart from seaweed, is single-celled algæ and there are also fungi. Algæ contain carotenoids which can be converted to vitamin A, lipids which include essential fatty acids, and some blue-green algæ even contain B₁₂. What I’m not sure about is the evolution of yeast. Although there are commensal yeasts on animal bodies and also pathogenic yeasts, I think probably the yeasts we’re familiar with depend on flowering plants just like many animals today do. As far as fungi more generally are concerned, the fossil record is unsurprisingly very poor, and the question of toxicity arises. Would toxins in fungi be absent before animal land life due to the lack of pressure to avoid their fruiting bodies being eaten, or is it more that the compounds in fungi which happen to be toxic satisfy other functions in the organisms and they’d just be poisonous anyway?

Once one considers a world where the only land life is fungal, the planet is almost alien in its conditions. There wasn’t enough oxygen to support human respiration in the atmosphere and ultraviolet radiation wouldn’t have been filtered out of sunlight due to the absence of an ozone layer. Whereas it would be possible to survive in dietary terms as a vegan in the early Palæozoic, it involves quite a lot of research only really possible on living organisms and also a high-tech approach to food production.

To conclude, this is not just an abstract exercise. Not only does it reveal the close connections between us and the plants with which we have co-evolved, but it may also become more relevant when one considers that one of the influences we have on the biosphere is to push it back into prehistory. Jellyfish, one of the first animals, are much more common than they used to be due to our influence on the oceans, and “algal” blooms are also more common. Perhaps we will end up having to survive on a planet once again devoid of complex land life, flowering plants and the like, and in such circumstances a plant- and fungus-based diet may turn out to be the only option.