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. And dozens of other fruit species occasionally have individual trees producing giant fruits high-up, that are hundreds of times larger than necessary to spread their seeds.

Now there is no explanation for all this recessive fruit gigantism in today’s world. But it does fit very 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 fruit up-high, and thus they 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 for seed spreading. Thus the macro-fruit trees were uniquely able to spread into the new habit zones constantly created by climate change, droughts, forest fires and other causes. And this gigantism “network effect” is what caused the giant dinosaurs as well as the giant fruit.  

Eventually, small animals started climbing up straighter and straighter trees, and jumping between limbs to get at the fruit. Then the fruits developed countermeasures against the “rats” trying to cheat their immensely costly seed spreading system.  Here is why most fruits have thick and bitter skins,  and more importantly, why most 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 small, 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 however, 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.

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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

Seed spreading is key to animal evolution

1) Seed-spreading caused amphibians by feeding them. Seed spreading pulled vertebrate life from the water by feeding it.
Before land animals (tetrapods) evolved about 370-mya (million years ago), seed spreading was a huge problem for plants. Wind and insects are not really effective for spreading seeds, so some plants probably also evolved to use rivers to spread their seeds.  At some point,  fish began eating the river borne seeds or spores.  And after this, the fish began eating overhanging seeds.  Then they began flopping onto land to get more of the nutritious seeds.

Aquatic animals tend to be tall and thin, terrestrial animals tend to be short and wide. Here is a fish that seems quite terrestrial, or at least littoral.

It was at this point that something remarkable happened. Seeds began passing through this terrestrial fish, and they began passing through on land, some distance down the river, and far from where the seeds came from.  Suddenly this one type of  plant became very successful, and it suddenly had a greatly scaled its breeding network.  And at the same time, the fish eating this plant’s seeds had a huge supply of food, so it also scaled its breeding network.

The limiting factor seems to have been the ability of the fish to move far from the water in search of seeds. And the individual fish that could do this both found ample food and increased the habitat zone of their symbiots.  Thus the networks dynamics of seed spreading caused fish to venture farther and farther onto the land to find seeds to eat and spread.   And this is where the amphibians came from, beginning about 370-mya. This is also where the conifers (pine, juniper, holly) came from, also about 370-mya. The timing coincidence is because the two are symbiots.

2) Seed-spreading caused reptiles by feeding them. Seed spreading pulled vertebrate life far from the water by feeding it.
Then 320 to 310-mya, we start to see animals that did not go back to the water to breed, namely the reptiles. This was about the same time when cycads evolved. Cycads are palm-like plants which today put coconuts and giant bundles of dates high up a long stalk.  The early cycads were however short like sago plams.

Some experts think the first proto-Cycads began around 325-mya, although some experts with a stricter definition think that it was as late as 280-mya.  Thus it appears that the fruiting Cycads were the main symbiot of the first non-amphibious reptiles. Thus it appears that fruit spreading pulled animal life away from the water.

3) Seed spreading caused plants to offer fruit
After some time, the plants began helping their symbiots (and the survival of their own seeds) by providing fruit nutrition outside the seed itself. This is why we have fruits of two parts. One is delicious, soft, sweet fruit, and the other is the hard inedible part, like an avocado, peach or mango pit. The delicious edible fruit was the bribe, and the hard inedible seed is the part to be swallowed whole and spread.

This fruit bribery is what the angiosperm plants (the flowering plants) evolved for. And we do find fossilized angiosperm-like pollen from about 245-mya.  And while the first dinosaur fossils officially come from about 225-mya, their proto-dinosaur ancestors could have easily been angiosperm symbiots say 20-million years earlier. 

Here is a durian sliced in half. Note the thick, woody, and spine encrusted  husk. Note the big seeds within a thick layer of fruit. Note how the plant evolved to kill-off two seeds so the other seeds would be thicker and harder to digest.

The arms race of the plants (to spread their seeds farthest) led them to give all they could to their most beneficial seed spreading animal symbiots (as we see in the highly nutritious durian above). Thus it is the benefit of terrestrial seed spreading that caused the plants to “draw” the fish out of the water by nourishing them with fruit. Also, in a similar way, seed spreading caused the plants to “draw” the animals into the treetops for reasons that we will get to next.

4) Seed-spreading caused dinosaurs to be big
5) Seed-spreading caused tall trees with macro-fruit
Lets go back to before birds and bird-based seed-spreading evolved. At this time, if plants wanted animals to spread their seeds, they had to give away a fruit-snack just like today. But at that time, the seeds swallowed by the biggest and highest-reaching animals tended to be spread further, giving that tree species an important advantage over seeds swallowed by smaller creatures that did not need to constantly roam in search of food.  So before the evolution of birds as effective seed spreaders, survival favored trees with giant, nutritious fruits high up, along with their giant animal symbiots capable of reaching this fruit.  This is the evolutionary force that both caused dinosaur gigantism, as well as tall trees.

6) Seed-spreading caused Dangling fruit on break-away stems
Small animals were constantly climbing the trees to steal the macro-fruit and cheat the system. This caused the plants to evolve dangling fruit on break-away stems.

7) Seed-spreading caused birds
The birds came from the cheating animals that survived the fall when the dangling fruit broke-away. First they survived small falls, then larger falls. Then they learned to glide between trees… of greater and greater distance. Then they were flying.

8) Seed-spreading caused mammals
The mammals came from the animals that were so small they either didn’t trigger the fruit to fall, or so inconsequential their group would prosper anyway if this happened.

9) Seed-spreading ended the giant dinosaurs
Once birds evolved, plants had a more efficient means of spreading their seeds, and the plants that continued to provided macro-fruit for dinosaurs were wasting huge amounts of energy on seed spreading. These were at a huge disadvantage and eventually either adapted or mostly died out. Once the macro-fruit trees all started catering to the birds, the dinosaurs died out.

More than a theory of dinosaur evolution
Here is a single theory that explains most of the most important developments in animal evolution.

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 gymnosperms, 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 60,000 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.

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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.

This 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 close to the ground, but during the time of the giant sauropods, they grew quite far above the ground. We can tell this by measuring the reach of the biggest seed-spreading sauropod symbiots. We can also tell this by graphing the maximum fruit growth ceiling for individual trees of the various species. Also, the above drawing is in error in two important ways. First, all existing reptiles seem to prefer meat, or insects, or fruit to leaves.  Also, the above reptile has a mouthful of leaves.  And Secondly, the position of the sauropods should be shown in one of the two positions below if he is 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. Also, the reptile’s neck might even spiral the trunk of the tree a bit, for added stability.  Later, if the dinosaur grows full, or if there is no need to reach, he sits down and feeds on the lower branches.

The twistable thumb claw
At first, one group of reptiles specialized in eating the fruit of the tallest trees. Early on, these developed the “twistable thumb claw” (like the prosauropod Plateosaurus). This helped the dinosaur stand up on its hind legs and grasp a tree for support,  and stability.  Then after a while, there was this co-evolution feedback-loop where the trees got taller and the animals with thumb claws (sauropods) became bigger and developed longer necks.  This is because the biggest animals spread their seeds furthest. It is also because long necks were the most efficient way to reach the fruit.  And this fruit-bait for seed spreading was the driving force of an entire macro ecosystem that was primarily based on size and high-reach, and these characteristics above all others.

Also, 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.

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 the first grand unifying principal (otherwise known as 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.

And 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 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. Never mind speed, or intelligence, or metabolism. During the age of dinosaurs, animals needed to get tall to reach the big fruits, to get energy to survive and reproduce. And animals also needed to get big to support the lengthy digestive tracks capable of breaking-down the fructose-rich fruits that had evolved to favor slow-digesting animals.

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 35 African forest elephants, or 17 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 35 African forest 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