Earth's wobble killed off mammal species

[Dann Pigdon <dannj@alphalink.com.au>]

For all those who've ever wondered about the 2.5 million year average 
lifespan for mammalian species... 

--

Earth's wobble killed off mammal species
11 October 2006
From New Scientist Print Edition. 

Mammalian species are known to last an average of 2.5 million years before 
being snuffed out, but nobody had been able to figure out why. The reason, 
it turns out, may be linked to regular wobbles in Earth's orbit. 

Jan van Dam from Utrecht University in the Netherlands and colleagues 
reached this conclusion after studying the fossil record of rodents from 
central Spain over a 22-million-year span. This showed a link between rodent 
extinction events and the climate record... 

Continued at: 

http://www.newscientist.com/article/mg19225735.300-earths-wobble-killed-off- 
mammal-species.html 

(possible line-wrap alert) 

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Dann Pigdon
GIS / Archaeologist         http://heretichides.soffiles.com
Melbourne, Australia        http://www.geocities.com/dannsdinosaurs
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