Giraffe and its' relatives - Nov 28

 Let us talk about giraffes and their relatives, just because.

The modern giraffe…consists of no one has a definite idea of how many species of the modern giraffes there are: an 8, a 4, and a 3-species family trees are proposed, and so far, not a single one out of them has won, all three theories are equally valid. That said, all of the giraffes are the world’s tallest mammal; they all are browsers, and eat leaves and other parts of trees and shrubs rather than grasses and other herbaceous plants. This is important, as grasses tend to regrow after they had been cropped by such mammals as the zebra, whereas tree leaves… also regrow, eventually, but at a much slower pace than how the grasses do. Therefore, many African savanna trees have evolved… some, as the acacias, have spines and symbiotic relationship with ants, (rather than termites), while the baobabs are flat-out huge and can handle the giraffes through their sheer size and bulk… eventually. Still, we digress.

Regardless of how many species of the modern giraffe there is, the modern okapis are represented by a single species, the, well, modern okapi. It is also called ‘the forest giraffe’, ‘the zebra giraffe’ and the like, but scientifically, it is named Okapia johnstoni. It is smaller, or rather – shorter than the ‘true’ giraffe of the African savanna, which means that it is less specialized than its’ cousin (cousins?) is.

Why? Because – proportionally – the okapi has a more varied diet than the giraffe from the start. It, too, eats foliage rather than grasses, as does the giraffe… but it does so because there is far fewer ‘true’ grasses in the jungle where it lives. The grasses are plants of open spaces, because in enclosed spaces bigger plants – shrubs and trees – block out the sun, and the herbaceous plants that live in forests – whether temperate or tropical – are more shadow loving than their grassland counterparts are. …Yes, this is generalization, but you get the point. Back to the okapi.

Again, it eats foliage and other parts of trees and shrubs, (the non-woody ones), and has many similarities to the giraffe, but because it lives in a proportionally more abundant and varied ecosystem, it is smaller and less derived than the giraffe is. In addition, there are fewer big herbivores in the jungle, as opposed to the savanna, and they tend to be smaller in size – the okapi, the African forest elephant, the forest antelopes, the pygmy hippo, even the non-white rhinos of the world – they all are smaller than their savanna-dwelling relatives are. In part because they’re living in tighter conditions, in part – because there’s less competition between the species, and fewer big predators as well – out of Africa’s ‘big five’, only the leopard enters the jungle, and it doesn’t appear to be attacking okapis regularly, for example, or giraffes for that matter. As such, the okapis do not need to get as big as the giraffe, as the giraffe’s size – or height – protects it from the leopards, lions, etc. (Moreover, the baobab’s size protects it from the giraffes, elephants, etc.). What next?

From the close relatives, to the more distant ones – the American pronghorns, the last members of the giraffes’ sister group. However, it is known as ‘the American antelope’ and ‘the pronghorn antelope’ among other monikers, this mammal – Antilocapra americana – is much less derived than the ‘true’ antelopes of the Old World is, and proportionally, it is much more closely related to the giraffe and the okapi. That said, physically, ‘on the outside’, the pronghorn is reminiscent… of the gazelles of Africa and Asia.

Eh, ok, gazelles are antelopes, in a matter of speaking. However, they are also antelopes that evolved for speed; they are light-bodied, long-legged and gracile, as opposed to something like the eland, which is built more like a cow, quite robust, or even the gnu, which is more of an endurance marathon runner instead. The American pronghorn, however, is also a marathon runner, having evolved in a time period when North America had its’ own cheetah species, (more closely related to the puma than to the modern Old World cheetah), and cheetahs are the ultimate sprinters – but we digress. These days, North America has no cheetahs, but what it does have is an Old World civilization that restricts’ the pronghorns’ (and the bison’s’, the peccaries’, etc.) prairie habitat, causing their populations to plummet regardless, much more efficiently than any cheetah would be able to… However, for us, what is important here and now that while the ‘true’ giraffe is a savanna foliage specialist, and the okapi is a jungle foliage generalist, the pronghorn is a prairie grass generalist instead. Is there anything left?

Actually, yes – the chevrotains or the mouse deer. Contrary to their names, the ‘rest’ of the deer are not close relatives of these mammals; the ‘true’ deer, and the musk deer, are much more evolved than the chevrotains are.

Let us try again. Among the modern ruminants, two groups stand above the rest. One group are the bovids – antelopes and gazelles, wild cattle, sheep and goats. Moreover, the second group are the deer. There are the ‘true’ deer, which consist of two subfamilies – the American deer, (with some exceptions, such as the moose, the caribou and the roe deer), and the Old World deer, (with some exceptions, such as the wapiti). The second family are the musk deer, (6 or 7 species), which are the sister group to the ‘true’ deer. Moreover, the mouse deer/chevrotains?

…They are much less derived than the ‘other’ deer – in fact, the rest of the ruminant artiodactyl mammals – are, and proportionally, they are much more closely related to the giraffe, the okapi and the pronghorn.

What do chevrotains look like? Tiny, vaguely deer-like animals with hooves, but without antlers. Some have also proportionally big canine teeth, superficially like the much bigger musk deer. (Actually, the musk deer are quite smaller than the ‘real’ deer, but they are still quite bigger than the mouse deer). They live in jungles – one in Africa, the rest – in Asia. That is because in Africa, their niche is taken over by the antelopes, i.e. the duikers and the Neotragus species, but that is another story.

Anything else? Right, the water chevrotain – the outsider that lives in Africa, rather than in Asia – is omnivorous, the others are less so, and all are found close to water. Put otherwise, not unlike the giraffe, the mouse deer are specialized – they have a very specific econiche in which they live, and this enables them to survive, avoiding competition with more derived herbivores. Only not, for in Africa that same econiche is taken over by those more derived herbivores – small jungle antelopes, such as duiker, and so only the water chevrotain Hyemoschus aquaticus is able to survive there, by being the most aquatic and most omnivorous out of them all. As Po the giant panda told the snow leopard villain of the first ‘Kung Fu Panda’ movie, “there’s no ultimate secret”, there is no ultimate solution to anything.

Let us conclude. On our narrative about the giraffe, we met four very different types of even-toed mammals. As we look at them, we see the giraffe, browsing from the treetops of the African savanna, the pronghorn, grazing on the grasses of the American prairie, the okapi, who is eating the leaves in the African jungle, and the mouse deer, which are scurrying through the undergrowth of Asian, but also African jungles, eating various general plant matter. They all look different from each other, but all are also more closely related to each other – proportionally – than to any other plant-eating mammal. This, then, is the wonder of evolution.

Quarantine entry #19 - April 9

Obligatory disclaimer: real life sucks. Not only COVID-19 is still going on strongly, this morning we had a very nasty snowstorm. Fortuitously, we stayed inside, and now the storm is over, (it is the beginning of April, after all), and nature is coming back out – the birds are flying, singing, fighting over their nesting territories en masse, showing just how resilient life on Earth. The storm passed and is over; COVID-19 too will pass and be over and life will return to normal. …Well, relatively so, seeing how the politicians, businessmen, and who else have you, are trying to take advantage of the lockdown and all, are trying to take advantage of the lockdown, and it is all coming down like a great big mess; people are fleeing into the literal woods to escape both COVID-19 and everything else. What next?

Let us talk about the giraffe. Why the giraffe? Because it is unique. There is no other mammal on the modern planet like it. If the modern elephants represent the last scions of an ancient dynasty of herbivorous mammals that fell due to the competition with the artiodactyl mammals, then the modern giraffe is one of those evolutionary cousins of the main dynasty – aka the antelopes, gazelles, wild cattle, sheep and goats – that had its’ heyday in the past, (the Miocene & the Pliocene epochs), but is largely gone, these days.

Pause. The entire taxonomic-biological family of the giraffe consists of the giraffe, and the okapi, aka the forest giraffe. Frankly, the latter name is not used very often, because the okapi is only like the giraffe in the most generic ways; you can see the family similarity, but nothing more. With an effort, you can confuse an Asian elephant with an African one, or an Asian rhinoceros with an African one, but an okapi with a giraffe? Just no. …The families of the okapi and the giraffe have diverged during the Miocene slash the Pliocene, around 11.5 MYA, and the two have never been in contact since.

The okapi family is represented by a single species – the okapi itself. The giraffe, on the other hand, is murkier, as people in charge of biological classification still have not made their mind as to if there is just a single giraffe species, or four of them, or what. Even if there is just a single giraffe species, it may have up to nine subspecies, which is a lot. …Of course, with humans hunting them for all sorts of reasons, or even without any reasons at all, because we humans can be assholes, they may not be around for much longer, but that is not a good thing.

…Yes, COVID-19 has hit humans, even in Africa, hard, so they may not be up for the giraffes, but no one knows exactly how it affects other animals; for example, a tiger in Bronx zoo was discovered to have it; and with giraffes slash okapis, it is anyone’s guess.

So, why is the giraffe so unique? Because it is a very specialized animal – it is not big: it is tall. A good portion of the giraffe is its’ disproportionally long neck and legs; the neck, I think, amounts for about half of the giraffe’s body length, (while in case of the okapi it is about 30%, on average). Just like a human’s, the okapi’s and the giraffe’s neck consist of only 7 vertebra, but the giraffe’s are the most massive one out of the three by far, both in size and in weight. Isn’t trivia fun?

What next? …Um, aside from the humans, the main enemies of the giraffe are the African lion and the Nile crocodile; no one else really wants to tackle and fully-grown giraffe – compared to an elephant or a rhinoceros they may look like great big fragile land kites or something, but their head-butts are painful, and their kicks can be deadly. African lions, however, are known to tackle African bush elephants, (not fully grown, but not just calves either), who are even stronger than the giraffes are, and so they do overpower giraffes by working as a team, on occasion.

The Nile crocodile, on the other hand, is more of a case by case situation – it is a solitary hunter; crocodiles of these species may gather together to feed, (their anatomy of jaws and teeth makes it easier for them to feed together, rather than separately, on something bigger than what they can just swallow whole)… where were we?

Ah yes, unlike the African lion, the Nile crocodile is a solitary hunter, but a social feeder, especially if the prey is big – say, a dead African hippo. Then the not-quite-social crocodiles gather and tolerate each other, more or less, as they feed – with ‘tolerate’ being the key word here. The African lions hunt together, (though there is plenty of case-by-case variation there), and their society is quite complex, (cough, TLK is full of baloney, cough), but they and the Nile crocodiles do not have anything in common aside from both of them living in Africa.

…Yes, we have discussed the ‘African lion vs. Nile crocodile’ AFO episode a while back, and spoiler alert – the lion lost, (and the giraffe was not involved at all), which is fair: a male African lion is a fighter, but it is a team fighter, and on its own, it rather has a disadvantage against the crocodile. Plus, on that episode team AFO really did its’ homework, and their deduction that the Nile crocodile was a better fighter than the African lion was justified, so there!

Back to the giraffe? Er, did it leave while we were dealing with the lion and the crocodile? Why, we have not even mentioned the non-avian theropod dinosaurs, aka the meat-eaters, are the goal of a real discussion of whether they did hunt together as the African lions do, or just fed together, as the Nile crocodiles? And what did they feed upon? Sauropods, among other things, just look at the second episode of WWD, or the fifth episode of ‘Planet Dinosaur’ (2013), for example! Are sauropods like the giraffe?

No, not exactly. Some are – that is the Brachiosaurus and its’ relatives. Others are not – rather, they are big, (aka the elephant) – that is Argentinosaurus and the rest of the titanosaurs; or they are just long – aka Diplodocus and its’ relatives, (including the Apatasaurus). Yes, we are generalizing here so hard, but the thing is that many of the sauropods were built different from the giraffe, and many of them were not built like it.

Moreover, neither was the extinct Indricotherium, or whatever it is named now, (see the third episode of ‘Walking with Beasts’). Just like the extinct titanosaurs, or the existing elephants, it was big rather than tall, and quite proportionate. Why did it die out? Because not unlike the giraffe it was a specialized mammal, designed to eating foliage, and as the savannas, prairies, steppes, etc. spread, the Indricotherium could no longer survive. With the modern giraffe – it is pretty much the same thing: the giraffe survives alongside all of those antelopes and gazelles by being the best foliage eater in the African grasslands – a very specialized niche, to be sure, but it does allow the giraffe to survive over more of Africa as opposed to the more generalized okapi, which exists only in parts of the African rainforest, and whose overall population is worse off than that of the giraffe. Evolution and ecology sometimes play strange tricks upon animals!..

…Well, this is it for now; see you all soon!