Posts Tagged ‘population’
whales in the post-whaling world, inter alia
stranded
We’re emerging, or hopefully have emerged, not only from the whaling period, but from the Sea World and Marineland period, when we prized cetaceans for their ambergris and such, and the circus antics we encouraged them to perform, all of which did great damage to their wild populations. The larger baleen whales were particularly affected by human depredations, as the Royal Society essay, linked below, tells us:
Nearly all baleen whale populations were severely impacted by whaling, and only some have recovered to anything like their pre-hunt densities. We expect most mammals to show some degree of flexible responses to ecological conditions, including conspecific density, so we cannot really know the extent to which our current picture of baleen whale sociality is of a markedly shifted baseline as opposed to the conditions under which it primarily evolved.
It remains to be seen whether previous migratory patterns, so disrupted during the whaling period, can be reconstituted. In any case, female bonding, on both a horizontal and vertical level, looks to be key to baleen sociality, as with other cetaceans. Toothed species are more common, and more various in habitat and behaviour, with the smaller species having ‘highly dynamic fission-fusion societies’, but the mother-calf relation is always key. The calf initially tags along with the mother in ‘echelon position’, a kind of diagonal following used in military training and in cycling. This tends to hamper the mother until the calf grows to be a stronger swimmer.
The cetacean sleep pattern is unihemispheric, meaning that one half of the brain is always awake and alert, something that is clearly essential and must have evolved reasonably rapidly to enable an underwater life which also required oxygenation, remembering that they had previously been land mammals. Fish obtain oxygen from the surrounding H2O via their gill filaments, which are full of networks of capillaries, providing a large surface area for the exchange of gases (oxygen and CO2) and other nutrients. Fish essentially breathe in oxygen-rich water, which, after processing through the gills, is expelled, largely depleted of oxygen, through the sides of the pharynx. Whales etc inhale and exhale through their blowholes, meaning of course that they must surface to breathe. Think of it as a nostril, which is tightly closed except when surfacing. For dolphins, the exhaling (first) and inhaling process takes only a fraction of a second. Surfacing, breathing dolphins might be appearing to blow water out of their blowholes, but this is just water blown off from the region around the blowhole.
Anyway, returning to the matter of survival, sperm whales seem to be slowly recovering from the depredations of humans. They’re so named because of the spermaceti, an oily-waxy stuff found in their ginormous heads, which somehow helps with echo-location and navigation. This spermaceti is found in some other whales, but the sperm whale gets its name for the volume of the stuff it carries – as much as 1900 litres per whale. From the 17th century, whales were hunted for this stuff – used in oil lamps, candles and such. Ambergris, produced in the digestive system of sperm whales, and extruded like shit, is prized for its odour, and probably also for its rarity – only a small percentage of sperm whales have been known to produce it, and it only rarely washes up on land.
The major threat to whales in general, now that they’ve gained acceptance, even a degree of worship, by humans, is overfishing, though this is actually affecting top predator fish, such as sharks, tuna and billfish, even more. Sharks in particular, are now one of the world’s most threatened marine creatures.
I suppose you could say that the future of whales is as much in the hands of humans as is an untold number of creatures we share the planet with – elephants, orang-utans, bonobos, chimpanzees, pangolins, leopards, tigers, mountain gorillas, rhinos, turtles, gray wolves, to name a few. Even insects are suffering from our activities, as Oliver Milman’s The insect crisis has revealed.
The human population continues to grow, and some, I hear, are happy to aim for a population of more than 20 billion. Do they think this can be done while preserving life’s variety? Many of the forums on questions like these don’t even consider the impact on other species. My own view is about improving life for the humans now suffering, of which there are millions. Quality of life rather than quantity is surely the key.
References
https://pmc.ncbi.nlm.nih.gov/articles/PMC6664132/
https://en.wikipedia.org/wiki/Fish_gill
Carl Safina, Beyond words, 2015
Oliver Milman, The insect crisis, 2022
https://au.whales.org/whales-dolphins/how-do-whales-and-dolphins-breathe/
childbirth, population, bonobos
A BBC pic from June 2021. This woman supposedly gave birth to ten, five by caesarian section, a new world record apparently. But it was all faked, it seems.
Given the craziness of that outlier nation of the WEIRD world, the USA, with its religious anti-intellectualism (in some states) and those states’ consequent ‘every sperm is sacred’ approach to abortion, I’m taken back to my childhood reading of the Guiness Book of Records, an extremely popular work published annually from 1955. My edition would’ve been from the 70s, but today’s internet may have rendered the collection virtually obsolete, methinks. Anyway, I recall being fascinated by the most grotesque facts, including – of course – the woman who gave birth to the most children. I don’t recall the number in my edition, but presumably this was the woman, and the number:
The greatest officially recorded number of children born to one mother is 69, to the wife of Feodor Vassilyev (b. 1707–c.1782), a peasant from Shuya, Russia. In 27 confinements she gave birth to 16 pairs of twins, seven sets of triplets and four sets of quadruplets. Although this seems to be a statistically unlikely story, numerous contemporaneous sources exist which suggest that it is true. The case was reported to Moscow by the Monastery of Nikolsk on 27 February 1782, which had recorded every birth.
My heart goes out to this woman, especially considering that, after all this enormous suffering, she isn’t even given her own name. Perhaps they didn’t bother giving names to women in Russia in them days – though to be fair, Catherine II, aka the Great, was Empress at the time.
Anyway, I remain extremely skeptical that any woman (okay, her name was Valentina), never mind her children, would survive such trauma (are the dates given above those of Feodor or his victim? – it’s unclear), and as for the husband, who went on to have a second wife (at the same time??!!) who gave birth to 18 kids via 8 confinements, what can be said…?
Happy to be a skeptic. Anyway, such records, fact or fiction, are unlikely to be repeated, partly because no woman, even in the most ultra-patriarchal remnants of the world, would put up with being so put-upon. As for kids these days, we’re learning to put quality before quantity methinks. Remember The population bomb? Apparently, this and other doomsday tracts of the late 60s and early 70s led to significant pressure for men and women to be sterilised in India in the following decade or so, as well as China’s One Child policy. But Ehrlich’s doomsday scenario, which he later described as a warning rather than a prediction, never eventuated, though it may have had some small influence on humanity’s slowing growth rate. My own view, when I consider the negative population growth of South Korea and Japan, and Australia’s fairly stable population in recent times, is that this is hardly a bad thing. If countries want to boost their populations, there’s always immigration, which, IMHO, has been a massive boon here in Oz. If nations prefer to be insular, along with negative growth, that’s surely their problem. I’m sure they’ll manage.
In any case, in the WEIRD world, especially among the relatively well-off, we’re having fewer children. Contraception and other resources are helping us to plan our families, if we’re making them.
Anyway, let’s forget about humans for a mo, and focus on a much more interesting species – bonobos:
Females bear one infant every five years or so with a gestation period of around eight months. One fascinating and unique behaviour recorded in bonobos happens during birth: other females have been known to gather around the pregnant bonobo and assist in the birth, similar to human midwives.
Bonobos’ low birth-rate is one reason they’re struggling as a species, so breeding in captivity, or in enclosed spaces within their own native regions, has become important. Another reason they’re struggling, though, is the same reason their non-human primate relatives are struggling. The behaviour of humans. Bonobo numbers are very hard to calculate, but here’s how Wikipedia puts it:
Conservation status. The IUCN (International Union for Conservation of Nature) Red List classifies bonobos as an endangered species, with conservative population estimates ranging from 29,500 to 50,000 individuals.
Let’s say 40,000 bonobos. The World Population Clock currently puts the human population at just under 8.2 billion. That means we outnumber bonobos by about 205,000 to one. We’re crowding out so many other primates, not to mention wild mammals in general, and even insects. But considering how excellent an example bonobos set, not only at childbirth, but during child-rearing, feeding time, the whole shebang of collective behaviour, all ultimately resulting from females taking power, we should be doing more than just safeguarding them, we should be taking note of this bonobo sisterhood at a time of unprecedented, and largely man-made, global crisis.
References
Paul Ehrlich, The Population Bomb, 1968
https://www.smithsonianmag.com/innovation/book-incited-worldwide-fear-overpopulation-180967499/
The over-population clock
a pro-democracy demo in Egypt, 2011
Canto: From time to time I’ve shown my students the world population clock (WPC), because I’ve brought my discourse round to it for some reason, and they’ve been mostly fascinated. And I’ve usually told them that the world’s population will level out at about 9.5 billion by mid-century, because I’ve read or heard that somewhere, or in a few places, but is that really true?
Jacinta: So you’re wanting to investigate some modelling?
Canto: Well yes maybe. I was looking at the WPC the other day, and was shocked at how births are outnumbering deaths currently. What’s actually being done to stem this tide?
Jacinta: Looking at the WPC website, there’s a lot more data there that might enlighten you and calm your fears a bit – if it can be trusted. Ok we went past 7.4 billion this year and you can see that so far there’s 70 milliom births compared to around 29 million deaths, and that looks worrying, but you need to look at long-term trends. The fact is that we’ve added a little over 40 million so far this year, with a current growth rate of about 1.13%. That figure means little by itself, but it’s important to note that it’s less than half of what the growth rate was at its peak, at 2.19% in 1963. The rate has been decelerating ever since. Of course the worry is that this deceleration may slow or stop, but there’s not much sign of that if we look at more recent trends.
Canto: Okay I’m looking at the figures now, and at current trends the projection is 10 billion by 2056, by which time the growth rate is projected to be less than 0.5%, but still a fair way from ZPG. The population, by the way, was two point something billion when I was born. That’s a mind-boggling change.
Jacinta: And yet, leaving aside the damage we’ve done and are doing to other species, we’re doing all right for ourselves, with humanity’s average calorie intake actually increasing over that time, if that indicates anything.
Canto: Averages can carpet over a multitude of sins.
Jacinta: Very quotable. But the most interesting factoid I’ve found here is that the current growth rate of 1.13% is well down on last year’s 1.18%, and the biggest drop in one year ever recorded. In 2010 the growth rate was 2.23%, so the deceleration is accelerating, so to speak. It’s also interesting that this deceleration correlates with increasing urbanisation. We’re now at 54.3% and rising. I know correlation isn’t causation, but it stands to reason that with movement to the city, with higher overheads in terms of housing, and with space being at a premium, but greater individual opportunities, smaller families are a better bet.
Canto: You bet, cities are homogenously heterogenous, all tending to favour smaller but more diverse families it seems to me. That’s why I’m not so concerned about the Brexit phenomenon, from a long-term perspective, though we shouldn’t be complacent about it. We need to maintain opportunities for trade and exchange, co-operative innovation, so that cities don’t evolve into pockets of isolation. Ghettoisation. Younger people get that, but the worry is that they won’t stay young, they won’t maintain that openness to a broader experience.
Jacinta: Well the whole EU thing is another can of worms, and I wonder why it is that so many Brits were so pissed off with it, or were they duped by populist nationalists, or are they genuinely suffering under European tyranny, I’m too far removed to judge.
Canto: Well, if there were too many alienating regulations, as some were suggesting, this should have and surely could have been subject to negotiation. Maybe it’s a lesson for the EU, but you’re right, we’re too far removed to sensibly comment. Just looking at the WPC now – and it’s changing all the time – it has daily birth/death rates which shows that the birth rate today far exceeds the death rate – by more than two to one. How can you possibly extrapolate that to a growth rate of only 1.13%?
Jacinta: Ah well that’s a mathematical question, and I’m no mathematician but obviously if you have a birth rate the same as the death rate you’ll have ZPG, no matter what the current population, where as if you have a disparity between births and deaths, the percentage of population increase (or decrease) will depend on the starting population and the end-population, as a factor of time – whether you measure is annually or daily or whatever.
Canto: Right so let’s practice our mathematics with a simple example and then work out a formula. Say you start with 10, that’s your start population at the beginning of the day. And 24 hours later you end up with 20. That’s a 100% growth rate? But of course that could be with 1000 additional births over the day, and 990 deaths. Or 10 more births and no deaths.
Jacinta: Right, which indicates that the total number of births and deaths is irrelevant, it’s the difference between them that counts, so to speak. So let’s call this difference d, which could be positive or negative.
Canto: But to determine whether this value is positive or negative, or what the figure is, you need to know the value of births (B) and deaths (D).
Jacinta: Right, so d = B – D. And let’s set aside for now whether it’s per diem or per annum or whatever. What we’re wanting to find out is the rate of increase, which we’ll call r. If you have a start population (S) of 10 and d is 10, then the end population (E) will be 20, giving a birth rate r of 100%, which is a doubling. I think that’s right.
Canto: So the formula will be: r = S – E… Fuck it, I don’t get formulae very well, let’s work from actual figures to get the formula. It’s actually useful that we’re almost exactly mid-year, and the figure for d (population growth) is currently a little under 42 million. That’s for a half-year, so I’ll project out to 83 million for 2016.
Jacinta: So d now means annual population growth.
Canto: right. Now if we remove this year’s growth figure from the current overall population we get as our figure for S = 7,391,500,000 and that’s an approximation, not too far off. And we can calculate E as 7,474,500, approximately.
Jacinta: But I don’t think we need to know E, we just need S and d in order to calculate r. r is given as a percentage, but as a fraction it must be d/S. And this can be worked out with any handy calculator. My calculation comes out at 6.6% growth rate.
Canto: Wrong.
Jacinta: Yes, wrong, ok, a quick confab with Dr Google provides this formula. d = ((E – S)/S).100. But we already have that? E-S is 83 million. Divided by S (7,391,500,000), and then multiplying by 100 gives a growth rate annually of 1.1229%, or 1.12% to two decimal places, which is not far off, but significantly less than, the WPC figure of 1.3%. I must have stuffed up the earlier calculation, because I think I used the same basic formula.
Canto: Excellent, so you’re right, my fears are allayed somewhat. Recent figures seem to be showing the growth rate declining faster than expected, but let’s have another look at the end of the year. Could it be that the growth figures are higher in the second half of the year, and the pundits are aware of this and make allowances for it, or are we actually ahead of the game?
Jacinta: We’ll have a look at it again at the end of the year. Remember we did a bit of rounding, but I doubt that it would’ve made that much difference.
Some current national annual population growth rates (approx):
Afghanistan 3.02%
Australia 1.57%
Bangladesh 1.20%
Brazil 0.91%
Canada 1.04%
China 0.52%
India 1.26%
Iran 1.27%
Germany 0.06%
Morocco 1.37%
Nigeria 2.67%
Pakistan 2.11%
South Africa 1.08%
United Kingdom 0.63%
(These are not, of course, calculated solely by births minus deaths, as migration plays a substantial role – certainly in Australia. Some surprises here. The highest growth rate on the full list of countries: Oman, 8.45%. The lowest is Andorra with -3.61%, though Syria, with -2.27% on these figures, has probably surged ahead by now).