January 7, 2008
Meteor or Mosquitoes – Who Killed the Dinosaurs?
We all know the story - dinosaurs were supposedly wiped out by an asteroid over 65million years ago. However, it is now being suggested that it could have been disease-spreading mosquitoes and other biting insects that lead to their demise.
Husband and wife team George and Roberta Poinar from Oregon State University suggest that disease spread by mosquitoes, mites and ticks was probably the major factor that finished off the reptiles.
By changing the nature of plant life, these insects could ultimately affect plant eating dinosaurs, thus leading to the demise of their natural predators.
This theory could help explain why dinosaurs took so long to die off.
The most widely known explanation is that the extinction of dinosaurs was caused after an asteroid or comet hit the Earth between the Cretaceous and Tertiary periods. A secondary theory suggests that they were driven to extinction by massive volcanic eruptions in India, which led to extreme climate change.
However, George Poinar, a courtesy professor of zoology at Oregon State University, points out that they did not disappear immediately. According to he and his partner, their extinction was drawn out over hundreds of thousands or even millions of years.
The popular asteroid theory would have certainly led to an abrupt extinction. And certainly climate change would most likely have wiped them out in a relatively short time, he said.
The Poinars' theory suggests that emerging diseases spread by biting insects, combined with the spread of flowering plants, and competition with insects for plant resources, was "perfectly compatible" with a lengthy process of extinction.
The Poinars outline their theory in "What Bugged the Dinosaurs? Insects, Disease and Death in the Cretaceous," published by Princeton University Press.
The professors reported that examination of insects preserved in amber found organisms which can cause malaria, dysentery "and other abdominal disturbances".
The infections the insects carried would have caused repeated epidemics that slowly wore down dinosaur populations, which had little or no immunity.
Professor Poinar added: "Other geologic and catastrophic events certainly played a role.
"But by themselves, such events do not explain a process that in reality took a very, very long time, perhaps millions of years. Insects and diseases do provide that explanation."