Denver, Colo. -- Dinosaurs and elephants may have had similar patterns
of decline in their long slide to extinction, according to a Penn State
"If we look at the last five million years before extinction for both dinosaurs and proboscideans, we find a surprisingly similar pattern of extinction," says Dr. Roger J. Cuffey, professor of geosciences.
The Proboscideans -- mammoths, mastodons, stegodons and elephants -- are not quite extinct, but with only two species left, they are far reduced from their heyday. The African and Indian elephants are the remnant of what, at its height during the late Miocene, was a group of some 30 types of animals roaming the Earth.
"Interestingly, at their height, dinosaurs also have a diversity of about 30 species," Cuffey says.
Cuffey and Joey H. Eichelberger, a Penn State undergraduate, compared the diversity of dinosaurs and proboscideans over the last 5 million years of their existence in a poster presentation today (Oct. 30) at the annual meeting of the Geological Society of America in Denver.
"Most people believe that we understand the extinction of the dinosaurs now that we have proof of a large meteor event at the time of their final demise," says Cuffey. "The KT meteor was only the final death blow for the dinosaurs, they had been declining in diversity and number for at least 5 million years."
For the proboscideans, the final death blow will probably be by the hand of humans, but these elephant-like animals also suffered a gradual decline in species number over the past 5 million years and only now approach extinction.
Although dinosaurs and proboscideans ruled at different times, placing both decline curves on the same graph show that in their individual 5 million year periods, these giant beasts shared a very similar pattern of decline.
"No one has ever put both graphs on the same chart before," says Cuffey. "Because the patterns appear to be similar, perhaps we can learn something about the decline of the dinosaurs from the more recent decline of the elephants."
Cuffey notes that both groups of animals were the largest creatures of their times and probably had few natural enemies. The cause of their demise was probably not one single element, but a complex mix of factors that effected food supply and habitats. Because the proboscidean decline is more recent, there is greater possibility of uncovering the complex set of events that could bring gigantic animals from glory to extinction.
EDITORS: Dr. Cuffey may be reached at 814-865-1293 or firstname.lastname@example.org