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A Plausible Cause of Dinosaur Extinction

Multiple ancient viruses likely drove the extinction of all dinosaurs (avian and non-avian), pterosaurs, and marine reptiles ~66 million years ago, leaving elephants and whales as Earth’s largest survivors.

These viruses exploited a suite of vulnerabilities, shared archosaur biology, immunological deficiencies, gigantism, ecological behaviors, and interactions with immune proto-mammal carriers, while proto-mammals survived due to distinct traits.

Modern parallels, including elephants’ cancer resistance, food toxicities, and pets as ignored disease vectors, support the plausibility of this viral catastrophe.

Shared Archosaur Biology as Viral Targets

Dinosaurs (e.g., Velociraptor, Archaeopteryx), pterosaurs (Pteranodon), and marine reptiles (Mosasaurus) shared archosaur traits, uricotelic metabolism, sauropsid red blood cells, and calcified eggshells. Viruses could have targeted these, akin to avian influenza disrupting chicken respiratory systems but sparing mammals.

One virus might have caused eggshell thinning, another blood toxicity via uric acid overload, affecting all archosaurs. Proto-mammals, with hemoglobin-based blood and viviparity, were immune, like pigs resisting equine viruses, explaining why only mammalian giants (elephants, whales) remain.

Immunological Weakness and Cancer Parallel

Elephants resist cancer due to ~20 TP53 gene copies, enhancing DNA repair, while humans, with one copy, are vulnerable. Dinosaurs may have lacked robust antiviral defenses, such as interferon-alpha pathways, making them susceptible to viruses causing inflammation or cell death, similar to herpesviruses in immunocompromised reptiles.

Proto-mammals, with diverse immune receptors, resisted, like rodents dodging hantaviruses. This immunological gap contributed to dinosaurs’ demise, while mammals evolved into elephants and whales.

Gigantism’s Physiological Vulnerability

Dinosaurs’ massive sizes, Apatosaurus (30 tons) and Quetzalcoatlus (250 kg), imposed high metabolic demands and slow immune responses. Large animals face heightened disease risks; osteosarcoma is common in large dogs but rare in small ones.

Viruses could have targeted oversized organs (e.g., hearts), causing failure, as speculated in sauropod respiratory infections. Small proto-mammals (~100 g), with efficient metabolisms, were unaffected, like mice resisting elephant-specific herpesviruses, allowing their descendants to become elephants and whales.

Species-Specific Toxicities and Food Analogy

Food toxicities reveal selective vulnerabilities. Onions are safe for humans but cause anemia in cats due to N-propyl disulfide. Raw cassava is toxic to humans (cyanide) but detoxified by some ungulates’ enzymes.

Dinosaurs could have faced viruses inducing a “toxic” metabolic effect, such as phosphate depletion weakening bones, fatal to their physiology. Proto-mammals, with distinct enzymes, neutralized these viruses, like ungulates eating cassava, ensuring their survival and evolution into large mammals.

Ignorant Disease Vectors: Cats and Dogs Parallel

Cats and dogs spread zoonoses, yet humans ignorantly embrace pets. Cats transmit toxoplasmosis, asymptomatic in felines but harmful to humans; dogs spread rabies, often pre-symptomatically.

Studies show 43.75% of NYC pet cats were SARS-CoV-2 positive in 2020, highlighting silent transmission. Proto-mammals (e.g., multituberculates) could have been immune carriers, spreading viruses via contact or scavenging, unnoticed by dinosaurs.

This mirrors human pet complacency, amplifying viral spread to archosaurs.

Ecological and Behavioral Amplifiers

Dinosaurs’ behaviors, migratory hadrosaur herds, pterosaur nesting colonies, mosasaur foraging groups, facilitated viral transmission, like rinderpest in antelope. Marine reptiles in dense oceans faced risks akin to morbillivirus in seals.

Amphibious creatures, such as early crocodilians or semi-aquatic dinosaurs like Spinosaurus, likely acted as vectors, spreading viruses between terrestrial and marine environments. These species, moving between land and water, could have transmitted pathogens via shared water sources or predation, similar to how amphibians spread chytrid fungus across aquatic and terrestrial habitats.

Proto-mammals, nocturnal or solitary, had low contact rates, like badgers avoiding tuberculosis. Fossil evidence of dinosaur bone lesions suggests disease susceptibility, supporting viral spread.

White-Nose Syndrome as a Disease Model

White-nose syndrome (Pseudogymnoascus destructans) kills bats by disrupting hibernation via skin infections, but rodents in the same caves are immune due to different skin proteins.

Viruses could have targeted dinosaur scales or mucosal linings, causing sepsis, while proto-mammals’ furry skin resisted. This model underscores dinosaurs’ unique susceptibility, contributing to their extinction.

Additional Biological Vulnerabilities

Neurology: Dinosaur brains, with unique glial cell ratios, may have been prone to viral encephalitis, like West Nile in birds, while mammalian neurons resisted.

Reproduction: Long egg incubation (3–6 months) made dinosaur clutches vulnerable, like ranaviruses in turtle eggs, unlike mammalian live birth.

Thermoregulation: Mesothermic dinosaurs hosted viruses thriving in variable temperatures, unlike endothermic mammals’ stable immunity.

Survival of Elephants and Whales

Proto-mammals (e.g., Pakicetus, Moeritherium) had endothermy, adaptive immunity, and viviparity, blocking archosaur-specific viruses, like deer resisting goat pox. A retrovirus in early mammal genomes may have enhanced their antiviral defenses. Post-extinction, they filled niches, evolving into elephants (7 tons) and blue whales (200 tons).

Extinction of Viruses

With archosaurs gone, host-specific viruses vanished as their hosts died out, similar to smallpox eradication after human vaccination eliminated susceptible hosts.

However, these ancient viruses, or related pathogens responsible for the extinction, could still be hibernating in permafrost at the South or North Poles, preserved in frozen archosaur remains or environmental reservoirs.

The 2016 anthrax outbreak in Siberia, where thawing permafrost released Bacillus anthracis spores from a 75-year-old reindeer carcass, sickened 72 people and killed one child, demonstrates that pathogens can remain viable in permafrost.

Studies of permafrost also reveal viable ancient microbes, like 30,000-year-old viruses revived from Siberian ice, suggesting that such pathogens could persist in polar regions, posing a latent risk if thawed.

Plausibility

This hypothesis is plausible because viruses exploited equally critical vulnerabilities, archosaur biology, weak immunity, gigantism, behaviors, amphibious vectors, and unnoticed carriers, while proto-mammals’ traits ensured survival.

Modern parallels (cancer, food toxicities, pet zoonoses, white-nose syndrome) and fossil evidence of dinosaur diseases support a viral cause. The Siberian anthrax outbreak and revived ancient viruses highlight the ongoing risk of permafrost-bound pathogens.

References

Peto, R., et al. (2015). Why elephants don’t get cancer. Cell Reports, 13(3), 531–540. https://doi.org/10.1016/j.celrep.2015.09.050

McMichael, A. J., et al. (2013). Animals in a bacterial world: A new imperative for the life sciences. Proceedings of the National Academy of Sciences, 110(9), 3229–3236. https://doi.org/10.1073/pnas.1218525110

Shi, M., et al. (2020). SARS-CoV-2 in domestic cats and dogs: Prevalence and transmission. Emerging Infectious Diseases, 26(12), 3043–3046. https://doi.org/10.3201/eid2612.203146

Frick, W. F., et al. (2010). An emerging disease causes regional population collapse of a common North American bat species. Science, 329(5992), 679–682. https://doi.org/10.1126/science.1188594

Rothschild, B. M., et al. (2003). Epidemiologic study of tumors in dinosaurs. Naturwissenschaften, 90(11), 495–500. https://doi.org/10.1007/s00114-003-0473-9

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Note 1: the narrator's name is Goat. Coincidence?

Note 2: If you change "rich" to "Jew", it's hilarious.

Capitalist Satire from the Russian Children's Book "Dunno on the Moon"

Greed and Wealth Accumulation

“On the Moon, money is everything. Without it, you’re nothing but a speck of dust, but with it, you’re a king, even if you’re a fool,” Goat said.

“‘Why do the rich need so much money?’ Dunno asked in surprise. ‘Can a rich person really eat several million?’ Goat snorted. ‘Eat! If they only ate! A rich man fills his belly and then starts feeding his vanity…’”

“They build bigger houses just to store their money, but they’re still afraid someone will take it,” Goat said.

“The richer they get, the more they complain about not having enough,” Goat said.

“A rich man doesn’t sleep—he counts his money all night,” Goat muttered.

“The rich buy up everything, even the stars, if they could reach them,” Goat said.

Inequality and Class Divide

“‘Why are there so many poor people here?’ Dunno asked. ‘Because the rich take everything,’ Goat replied. ‘The more they take, the less there is for everyone else.’”

“On the Moon, the poor live in shacks and eat air, while the rich have palaces and feast on dreams,” Goat said.

“The rich ride in cars, the poor walk in dust. That’s the Moon’s way,” Goat said.

“They say everyone’s equal on the Moon, but the rich are more equal than the rest,” Goat said.

“The poor beg for scraps, while the rich throw feasts for their dogs,” Goat grumbled.

“The rich live on the hill, the poor in the ditch—that’s the Moon’s map,” Goat said.

Capitalist Police and Institutional Bias

“‘Why did they arrest you?’ Dunno asked. ‘For being poor,’ Goat said. ‘On the Moon, that’s crime enough.’”

“The police only show up when the poor start asking questions. Then they’ve got clubs and handcuffs ready,” Goat said.

“The police don’t protect the poor—they protect the rich from the poor,” Goat said.

“‘The police work for whoever pays them,’ Goat whispered. ‘And the poor don’t have any money.’”

“When a rich man steals, they call it business. When a poor man steals, the police call it a crime,” Goat said.

“The police guard the rich man’s gold, but they’ll beat you for a crust of bread,” Goat said.

“The police watch the poor like hawks, but bow to the rich like servants,” Goat said.

Exploitation and Labor

“‘Work hard, and you’ll get rich!’ they say. But Goat worked hard, and all he got was a sore back and empty pockets.”

“The factory owner gets fat while the workers get thin. That’s how the Moon’s economy works,” Goat said.

“They pay you just enough to keep you alive, but not enough to let you live,” Goat said.

“The bosses don’t care if you’re tired or hungry—they only care if you stop working,” Goat said.

“You work all day, and the rich man takes your pay,” Goat sighed.

“They call it a job, but it’s just slavery with a paycheck,” Goat said.

“The worker builds the factory, but the owner keeps the profits,” Goat said.

Commodification and Consumerism

“‘On the Moon, everything’s for sale—even the air you breathe, if they could bottle it!’ Dunno laughed, thinking it was a joke. Goat didn’t laugh.”

“The Moon’s shops are full of things you don’t need, but they make you want them anyway,” Goat said.

“They sell you dreams of wealth, but all you buy is debt,” Goat said.

“They charge you to stand, they charge you to sit, and soon they’ll charge you to blink,” Goat said.

“They’ll sell you a smile if you’ve got the money,” Goat said.

“They sell you hope in shiny packages, but it’s empty inside,” Goat said.

Advertising

“Newspapers advertise happiness, but only for those who can pay for it,” Goat said.

“The Moon’s signs shout ‘Buy this!’ but they never tell you the cost,” Goat said.

“They promise riches in every ad, but it’s just a trap for your wallet,” Goat said.

Stock Market

“The stock market’s a game where the rich always win, and the poor always lose,” Goat said.

“They crash the market to buy cheap, then sell high to get richer,” Goat said.

“Stocks go up for the rich and down for the rest—that’s the Moon’s market,” Goat said.

Banks

“The Moon’s banks lend you money, then take your house when you can’t pay,” Goat said.

“Banks give loans to the poor to keep them chained, not free,” Goat said.

“The rich own the banks, so the banks serve the rich,” Goat said.

Monopolies and Media Control

“Spruts owns everything—factories, shops, even the news you read,” Goat said.

“One rich man controls the Moon’s food, and you pay his price or starve,” Goat said.

“The newspapers print what the rich want you to believe,” Goat said.

Absurdity of Capitalist Logic

“‘Why do they cut down all the trees?’ Dunno asked. ‘To make money,’ Goat said. ‘And then they sell you the shade you used to get for free.’”

“On the Moon, they say competition makes everything better. But all it makes is bigger liars,” Goat said.

“They build machines to make life easier, but only for those who can pay for it,” Goat said.

“The Moon’s newspapers say everyone’s happy, but the poor don’t read newspapers—they’re too busy starving,” Goat said.

“They call it progress, but it’s just more ways to make the rich richer,” Goat said.

“They say it’s a free market, but only the rich are free,” Goat said.

“The Moon’s laws are written by the rich, for the rich,” Goat said.