20,000—calorie jack-fruits . . . and long dinosaur necks to reach them

The record jackfruit weighed 45-kilos and had over 25,000 calories.

Today we occasionally see 20,000-calorie Jackfruits, 10,000-calorie durian fruits, and one-ton pumpkins with over 260,000-calories of nutrition. And dozens of other plant species occasionally have individual trees producing giant fruits high up above the ground, fruits that are hundreds of times larger than necessary to spread their seeds.  Why on earth are so many plant species occasionally squandering these huge amounts of energy?

There is no explanation for all this recessive fruit gigantism in today’s world. But it does fit well with dinosaur gigantism. So here we imagine a world before birds, where most trees bore giant fruits that interested giant sauropods (like brontosaurus). These trees put their giant fruit up-high, and thus the giant fruits were only eaten by the animals capable of reaching them. These were animals so big they had to constantly rove in search of food.  And at this time (before birds evolved), this was the best way  for trees to spread their seeds far away.

At this time, the plants that did not provide giant and costly meals to the sauropods had to rely on ineffective means like the wind and insects and small reptiles for seed spreading. Thus the macro-fruit trees were best able to spread into the new habit zones constantly created by climate change, storms, and forest fires. Thus it was seed spreading that caused the era of dinosaur gigantism on earth.

Small reptiles must have been selected for their ability to climbing up straighter and straighter trees, until they could climb straight up any tree.  At this point, the fruits developed countermeasures against the small animals trying to cheat their immensely costly seed spreading system.  Here is why most fruits have thick and bitter skins,  and more importantly, why nearly all fruit evolved to dangle on break-away stems.  

There were only two ways for animals to deal with the deadly break-away dangling fruit.  One way was to glide to the ground safely, and this is what caused the birds to evolve. The other way was to become so small, that they would not cause the fruit to break away:  and also so inconsequential, that one Jackfruit would feed a number of their kind for all their short lives. This second way is what caused the mammals to evolve.  

Eventually the birds became better and less costly seed spreaders than dinosaurs. Then energy efficiency and natural selection started favoring the trees that catered to the tiny birds with much smaller fruit and seeds. Then over a long period of time, many fruiting plants started catering to bird sized appetites instead of the massive dinosaurs and their costly appetites.  Then with less and less fruits to eat, there were fewer and fewer giant dinosaurs, until a big climate shock where all the remaining dinosaurs went extinct.

An 8-kilo durian will have over 10,000 calories of nutrition.

Again, fruits like the durian above were once in the treetops, where only the biggest, and slowest digesting long-necked dinosaurs could reach.  Before birds evolved, catering to the biggest dinosaurs was the only way for trees to spread their seeds far away.

Now, it is widely accepted that plants give animals a snack of fruit in order to spread their seeds. But what about macro-fruits like the 8-kilo durians we occasionally see?  These are much more than a snack for any animal living today,  and dozens of plant species occasionally produce giant individual fruits.

Throwbacks, not mutants
These giant fruits are not mutants but throwbacks. They are the plant genomes (many plant genomes) randomly trying an approach that worked for about 140-million years.  And taken together, the widespread existence of these super-costly macro-fruits in so many plant species tell us about a time when macro-fruits were normal.

An iguana eating fruit whole

Prosauropods and gymnosperms
The giant fruit, high up on trees, co-evolved with the giant reptiles.  In fact, the rise of the sauropods, including the earlier prosauropods came along with the rise of the  angiosperm plants (the flowering and fruiting plants) the seed and fruit bearing plants. In other words, as the seed-bearing and fruit-bearing plants rose in the plant kingdom, sauropods rose in the animal kingdom to spread them. This is because both were evolving as symbiots.

Here is a durian tree heavy with fruit for long extinct sauropod symbiots. Here is maybe 50,000 or 100,000 calories of nutrition on half a semi-mature durian tree. What else but dinosaurs could have been eating this spine covered, thick rind fruit high up on a tree?

If these papaya plants mature, the massive nutrition of their fruit might be over 10 meters up. What sort of giant animals did this plant evolve this crazy over-supply of nutrition to feed?

Durian fruit is as caloric as meat
Durian has about 1,470 calories per kilo.  This is roughly the same caloric content as raw beef tenderloin (1,480), and pork tenderloin (1,430), and whole turkey (1,410).  And it is much more than raw tuna (1,050), raw skinless chicken breast (1,140),  and bananas (950).  So an 8-kilo Montong durian, might have 10,000 calories, about the same caloric content as a 8-kilo turkey.  Now mature durian trees will each have dozens of these fruits hanging from them. So a grove of durian trees will have thousands of durian fruits. Also, if dinosaurs were relying on macro-fruit for most of their calorie intake, they still might be eating lots of leaves.

Seed spreading is key to tree survival
For trees in a forest, the first mover advantage has always been quite important. The first tree to spread its seeds gave a big advantage to its offspring. They got nearly all the light, and they left little light for later competitors. So the first mover (or seed spreader) generally won the race. Also having several fist-sized durian seeds spread in a large piles of dinosaur excrement fertilizer surely must have helped a great deal.

Seed spreading and habitat enlargement was the reward for trees species that could please and sustain their giant animal symbiots. These species prospered over the other species during the era of dinosaur gigantism. And again, this was before the advent of birds, so at this time, getting eaten by a macro-saur was the best way to for trees to spread their seeds.

Today most macro-fruits grow closer to the ground, but during the time of the giant sauropods, they grew quite far above the ground.  We might compare the maximum fruit growth ceiling for the various species to the reach of reared-up sauropods. Also, the above drawing is in error, the sauropods were obviously creatures that evolved to reach high up.  They should therefore be shown in one of the two positions below if they were feeding.

To start the sauropod is reared up almost vertically on his hind legs and mounted to a tree.  This is to maximize its reach.  The thumb claws on its front limbs are digging into the soft bark of the tree and stabilizing the tall and unstable reptile. The reptile’s neck might even spiral the trunk of the tree a bit, for added stability.  Later, if the dinosaur grew full, or if there is no need to reach high, it would rest it’s heavy back-half on the ground and feeds on the lower branches.

The twistable thumb claw
The sauropods (like brontosaurus) were the group of reptiles specialized in eating the macro-fruit of the tallest trees. Early on, (around 225-mya)  these developed the “twistable thumb claw” (like the prosauropod Plateosaur below). This and the long neck helped the dinosaur to stand up on its hind legs and grasp a tree for support, and stability. Sauropods had long necks because that was the most efficient way to reach the fruit.

The plateosaurs were up to 10-meters long.

In sauropod trackways, the thumb claw is not seen. It is widely held that sauropods held their thumbs up when they walked. So it is easy to imagine that the thumb claw was critically important to rearing up, getting the macro-fruit, and surviving.  And to prevent damage, the thumb claw was held up when the sauropods lumbered between fruit trees.  And just as the thumb claw could be held up it probably also could be lowered, or pressed down into a trees soft bark.

Above we see a right-hand sauropod thumb claw. This allowed the tall and unstable reared-up dinosaur to stabilize itself by pushing its thumb claws into the bark of the tree that it was feeding on.  The positioning is like when you grasp someone by the head with both hands, and have your four fingers behind their head, and your thumbs above their ears. This put the cut of the thumb claw at exactly parallel to the grain of the wood in the tree. In this position the claws would go in deepest and be most effective in stabilizing the tall and unstable sauropod.  Later sauropods titanosaurs lacked the thumb claw. Perhaps the loads became too great and the animals had to “hug” their trees instead.

Here we see thousands of calories of dates high up on a tree.  Why is this plant squandering all this energy?  Unless we accept that the plant evolved all this costly fruit to feed giant seed spreading symbiots, the giant amounts of fruit nutrition make no sense.

Myth: The dinosaurs died out all at once
In truth, from the start of the Jurassic erea, the macro-fruit trees suffered from constant attacks on their fruit bribes from legions of miniature cheating animals. Thus the macro-species (both animal and plant) started going extinct at an accelerating rate starting maybe 90-million years ago. Then, all of a sudden, 66- million years ago, all the remaining cold-blooded and giant animals went extinct.

There is a worldwide sedimentary soil layer that is iridium rich, right at this point in the sedimentary record.  And because meteors are iridium-rich, many people take this layer to mean that a meteor hit the earth 66-million years ago. However, meteors are not made out of iridium. Iridium traces are only slightly higher than on the surface of our planet. So having a detectable worldwide iridium anomaly layer implies quite an unbelievably large meteor. On the other hand, our own planet’s interior is also iridium rich. So the iridium might have been caused by one or more volcanos instead.

Digression: The first law of group evolution
The adaptation speed of an evolutionary network increases as an exponent of its size. It is basically another application of Metcalf’s law.  Briefly stated, it is that: “The value/ power/ speed/ adaptability of a network increases as an exponent of its size.” So every increase in a life form’s breeding population (the population of the species) will produce an exponential increase in the all-critical speed at which adaptation and evolution occurs for that species.

In other words, all life forms are not just in a battle to survive as individuals competing with other individuals of their own kind — But their species is also in a battle to survive against other species, and here the population of the species, the number of individuals in the evolutionary network determines the speed at which beneficial mutations occur. That in turn determines speed of adaptation, and that speed of adaptation in turn helps assure the survival of that species over other competing species.

Trees are no different from other life forms here. They are also in a battle to get the biggest breeding populations. Those species that were not able to acquire new territory tended to evolve slower and die out. Thus the tree species that could gain larger breeding populations tended to survive. And here, everything was about spreading seeds far. And before the advent of birds, the best way to do that was to get a huge slow-digesting sauropod like brontosaurus to eat your seeds.

Macro-fruit was for sauropods
The macro-fruit trees didn’t need any small animals climbing up and cheating the system, eating their precious fruit bribes and doing nothing to help spread their seeds. So evolution favored the plants that put their fruit up high, really high up, where only the biggest animals could reach. And evolution also favored the plants that had fruit with thick rinds, thorns and slow digesting fruit, as well as other counter-measures . And here the seed spreader’s size and slow metabolism was critical, because it produced an exponential increase in value to the plant (the first principal of network evolution again).

So before birds, plants needed to get tall, so that they could put their big, nutritious fruits bait and seeds high up. This was so only the biggest eternally roving animals would eat their seeds and spread them as far as possible. And at the same time, the main symbiots of these tall trees also evolved towards size and high reach. And in this pre-bird ecosystem,  high reach mattered above all else. Speed, intelligence, and metabolism did not matter. During the age of dinosaurs, animals needed to get tall to reach the big fruits, and thereby get enough energy to survive and reproduce.  And again, it was an ecosystem that was primarily based on size and high-reach, and these characteristics above all others.

However, once the birds became better seed spreaders than the dinosaurs, there was no need for the plant to invest energy in producing macro-fruit.  And once there was not much macro-fruit, there was little need for the animal to invest energy in the growing huge. So over millions of years one plant species after another stopped producing macro-fruit, and started producing today’s bird-sized fruits.

How gliding and expendable individuals
short-circuited dinosaur gigantism
Once the gliders (proto-birds) evolved to a point, the rules of the game changed. Nature (or more precisely evolutionary adaptation speed) favored larger populations of smaller flyers over smaller populations of larger flyers. And on the plant side of the symbiosis, the costly system based on hugely “expensive” durian-scale bribes began to collapse under its own extreme “cost”, and in species after species, trees started producing smaller fruits to feed the smaller flyers.

In other words, the trees that produced more bird-sized or rat-sized fruit leapt ahead of the trees that wasted huge amounts of energy producing 10,000 calorie durians. Then over time, the nature of our planet’s forests changed. And eventually, over millions of years, the planet’s trees all mostly stopped giving huge amounts of energy to macro-creatures, and macroism died out in favor of smaller seeds, smaller fruits and flight and high metabolism. And today we have to consider thousands of individuals to find one macro-fruit bearing tree.

Giant mutant fruit
It is worth repeating, that the giant “mutant” fruits we occasionally see today — the 700-kilo pumpkins and 4-foot-long papayas — are not mutants at all, but throwbacks. They are legacy dinosaur fruit varieties that many of plant genomes randomly try again from time to time. In some cases, the throw-back mutant is cultivated by man, but mostly all the huge dinosaur-sized fruits have now evolved to be today’s “normal sized” or bird size for today’s flight-enabled ecosystems.

Here some giant “throwback” passion fruit about 20x “normal” volume.  A great many fruiting plants (especially tropical plants) occasionally produce much larger fruits of the old dinosaur size.

Dinosaurs a concise natural history, Fastovsky Ch.8
“In all sauropodo-morphs, the gut must have been capacious… Sauropods likely had an exceptionally large fermentation chamber (or chambers) that would have housed endo-symbiots; that is, bacterial that lived within the gut of the dinosaur. The endo-symbiots would have chemically broken down the cell walls of the plant food, thereby liberating whatever nutrition was to be had. Considering the size of the abdominal cavity in sauropodo-morphs, these animals probably fed on foliage with high fiber content. Perhaps they also had low rates of passage of food through the gut in order to ensure a high level of nutrient extraction from such low-quality food. We can only conclude that these huge animals, with their comparatively small mouths, must have been constant feeders to acquire enough nutrition to maintain themselves. The digestive tract of a sauropod had to have been a non-stop, if low-speed conveyor belt.”

Fragrant durians
In some places they don’t even allow un-opened durians in taxis and on transit due to their extremely strong smell. And Jackfruits, mangos, and passion fruits are also quite fragrant.  And we humans have a terribly weak sense of smell, and we can easily smell an open durian 100 meters away. So it is not hard to imagine that a stand of durian trees might have called its animal symbiots from perhaps a kilometer or two away. And it is not hard to imagine that the giant lumbering sauropods were pausing every couple hours to relieve themselves. After all, nature would have favored the individuals that would better spread the seeds that would grow the trees that would produce the food that their offspring would live off of.

Fruit-eating reptiles today
How do fruit-eating reptiles eat peas, edamame, lima beans, petai, carob, or small cocoa pods that are suspended from above? Do they ever nibble the seeds out of their casings? And if we line up durian, avocado, carob, cocoa fruit, and other suspected macro-fruit, what does each species eat first? And which macro-fruits will carnivorous animals eat?

A 50-ton dinosaur, really?
The largest dinosaur supposedly had a mass of 50-tons. This is about the weight of 8 African bush elephants.  And we now know that dinosaur bones were largely full of air, like bird bones.  And the creature evolved to have super long necks, the longest (and hence lightest-weight) necks possible.  So it does sort of seem that the biggest dinosaurs were quite thin and airy, especially the front half.

How do you feed a 50-ton dinosaur on leaves?
This is about the weight of 8 African bush elephants, which actually eat a quite a large amount of fruit. How do you get that volume of leaves through the tiny head and mouths that sauropods have?

Giant stretch-lizards
I see them as giant stretch lizard. Clearly they evolved to reach something up high.  Was that leaves, or fruit, or both?  And if they were eating leaves, why did that need to be gigantic and reach high go away? In the age of dinosaurs, the tree fruit all looked like durians or jackfruits, and today it looks like linden wings which sort of float on the air.

Part 2 of:  20,000—calorie jack-fruits . . .  and long dinosaur necks to reach them






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