68 million years ago
Mean atmospheric O2
150% of modern level
Mean atmospheric CO2
6x pre-industrial level
4°C above modern level
Geologic Time Scale
Purgatorius and Bistahieversor
A rat-sized proto-primate of the genus Purgatorius hides amongst the undergrowth of a
cretaceous forest while a 30-foot-long, 2,000 pound tyrannosauroid dinosaur
of the genus Bistahieversor forages for
its next meal in what is today the western United States.
Purgatorius is the genus for several species of small omnivorous mammals
that are believed to be the among the earliest ancestors of modern-day
chimps, rhesus monkeys, and humans. The extinction of the larger and more
powerful dinosaurs may have been what led to world's domination by mammals
While there is no direct evidence that Purgatorius and
Bistahieversor ever shared the same wilderness, this image is yet
illustrative of the predator-prey relationship that characterized dinosaurs
and mammals for many millions of years.
© Walter B. Myers. All rights reserved.
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