101 CRAZY THEORIES ABOUT DINOSAUR EXTINCTION
Many of these theories have some element which makes them in some way reasonable.
However often they can only be related to a specific types of dinosaur, such as
herbivores or carnivores, or to those which lived in a certain habitat.
Changes in the atmosphere
Changes in climate.
Changes in the minimum and maximum temperatures
could have imposed stresses upon the dinosaurs that they could not adapt to in sufficient time.
Every possible change in climate appears to have been suggested for
the downfall of the dinosaurs.
Also try Climate change page!
- High levels of Carbon Dioxide destroyed dinosaur embryos.
- The 'breathing stimulus' of warm blooded dinosaurs was removed by low levels
of Carbon Dioxide.
- The oceans became stagnant due to high levels of Carbon Dioxide. Stagnant conditions mean that there would be no
oxygen for the any of the species living in the oceans, therefore there would be no food.
However this theory assumes that the dinosaurs all lived in marine environments.
- Atmospheric changes due to extensive volcanism and dust formation, which change the climate
and light levels. There could also be the release of poisonous substances such as selenium,
which could have been fatal, and also thinned the shells of the dinosaur eggs.
- Cataract blindness. If the dinosaurs couldn't see, there was no way of knowing
where they were going or how to find food.
There has also been a suggestion that caterpillars ate all the plants, leaving
nothing for the herbivores to munch.
- Too much Carbon Dioxide in the atmosphere due to the decrease of oxygen producing
algae, making the climate too hot.
This could have resulted in changes to the weather systems and rainfall patterns. A warmer climate
would also effect the female:male ratio of hatchlings, as sex is determined by incubation temperature
There could also be a decrease in the number male sperm produced, due to a warm climate which could reduce population
size. Finally a hot climate could have caused the dinosaurs to become overheated
in the summer if they were endothermic.
- Climate too cold, which meant embryo development was inhibited, reducing dinosaur
numbers. Furthermore if the dinosaurs were cold blooded, they would not have been able to survive
through very harsh winters, as they were too large to hibernate and were unable to keep their
body temperature at an appropriate temperature.
- Climate too wet.
- Climate too dry, making the environment arid and inhospitable.
- Nearby supernova explosion could heat the upper atmosphere, but also disturb the ozone layer and
produce large ice clouds in the high atmosphere, ultimately cooling the environment.
- Competition with other animals. Much of North America was invaded by Asian mammals,
however this explanation is only relevant to a specific part of the world.
Changes in the DNA of dinosaur cells.
A variety of genetic mutations could have resulted in weird and wonderful
creatures being created, which could not survive.
Floral Changes. There are numerous
related theories, due to the increase and dispersal of angiosperms
towards the end of the Cretaceous.
- A metabolic disorder relate to thinning of egg shells during incubation
due to variations in certain hormones. The embryos would die, as the shells would be unable to protect them from
predation and dehydration. Therefore within a very short space of time all the dinosaurs could have died
out if no infants survived.
- Also related to shell defects, is the idea that multi-layer egg shells formed,
with two or three shells on individual eggs, which would suffocate any embryo. This idea
is based on studies of French and Spanish dinosaur eggs found in the Pyrenees.
- Increasing Entropy , resulting in less order and the eradication of larger organised life forms.
- Epidemics of disease, however it is unlikely that a single epidemic could effect worldwide populations.
Also, an epidemic sufficiently large to wipe out the dinosaurs would also effect other animal
groups, but there is no evidence of such an effect.
However a weakness with many of these floral theories is that the main diversification of the plants
took place about 40 million years before the end of the Cretaceous. The rise of these plants
was also accompanied by a diversification of the herbivores, hence they would have adapted to
the changes in their diet. Furthermore, the rise of the angiosperms
would have been a relatively slow process, and therefore vegetarian species would have had
time to adapt to changes in their diet.
- Flowering plants are very efficient at producing oxygen, which will increase the
rate of metabolism in animal tissue. If this rate is too high, especially in large animals,
they may not be able to eat sufficient food to survive. As Schatz proposed, 'The dinosaurs
may have well burnt themselves up, or out!' With increasing oxygen the atmospheric pressure may have changed
such that the dinosaurs could not survive.
- There was a rapid evolution of fungi, especially poisonous species, which may have
contributed to the demise of the dinosaurs.
- As the plant life changed, there was a loss of habitats, especially marsh land.
Open land was also lost as forestation took place. Without the specific ecological environments
dinosaurs could not compete and survive.
- Flowering plants may have disagreed with the digestive system of the herbivores, as they produce
alkaloids, which are toxic.
- With the increase and diversification of plants that lose their leaves seasonally,
such as deciduous trees, there would have been less food available throughout the year
for the herbivore dinosaurs. If the herbivores died out, the carnivores would also have nothing
to eat, resulting in their death also.
The moon was extracted from the Pacific Basin, which would upset the atmosphere and climate.
- Changes within the oceans. If ocean sizes and distributions change, therefore
habitats are also affected. If the dinosaurs were could not to adapt to these changes, they
would have been unable to survive.
- Drainage of lakes and swamps, removed important habitats.
- Flooding destroyed habitats.
- Changes in the distribution of the oceans due to mountain-building.
- Spillage of fresh Arctic water into the oceans, resulting in lowered temperatures and
changes to weather systems.
- Reduction in the area of suitable terrestrial habitats due to increased sea-level.
- Regression , caused extinction on the basis that all dinosaurs were
marine creatures! Perhaps not applicable to flying dinosaurs.
- Transgression caused the bottom of the oceans to become stagnant and lacking oxygen,
which is essential for breathing.
- Overpopulation, could have resulted in severe competition, rivalry and warfare
amongst the dinosaurs. However animal groups also alive at that time, such as birds, somehow managed to avoid
- The effect of parasites, such as lice, worms and flies. They could have
overwhelmed the dinosaur population.
- Predation from mammals which ate the dinosaur eggs preventing new generations surviving.
- Over-predation , especially by the carnosaurs, who overkilled their prey, and hence had
nothing to eat.
- Overactivity of the pituitary gland, leading to excessive growth of bones
and cartilage . This would hinder the movement and efficiency of the
- Alternatively the pituitary glands may have malfunctioned, which lead to overgrowth
of frills, horns and spines, and such features impaired their ability to feed and move.
- Poisoning by uranium, which was leached form the soil.
- Racial old-age and over-specialisation. This includes evidence of enormous size,
loss of teeth and spiney growths.
- Reversal of the magnetic poles this would have created a temporary failure
of the magnetic shield, causing genetic damage and eventual extinction. However there
have been numerous reversals of the poles which do not have a corresponding extinction event.
- There was a decrease in sexual activity, and not enough dinosaurs were born.
- Slipped vertebral discs. This lead to severe back-ache, loss of mobility
and the inability to compete for food.
- Sunspots, these could have effected the climate and the atmosphere, to the detriment
of the dinosaurs.
- The explosion of a nearby supernova increased the radiation levels and cosmic
- Volcanism. There is evidence that the formation
of the Deccan Traps in India, took place at the same time as the dinosaur extinction. Excessive volcanic
activity can have significant effects on the climate. The Deccan Traps erupted on a very large scale,
and therefore could have had a major impact on the atmosphere at that time. This theory is the
main alternative to a meteorite impact, and it can explain many of the associated observations.
This includes the shocked quartz and the glassy spherules, see
The Impact theory for details of these observations.
- Increases in ultraviolet radiation due to destruction of the protective ozone layer
by solar flares .
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