Date: 11-29-90 21:44
Subj: Extraterrestrial Hunters?
DENVER -- The discovery of two giant dinosaurs in Wyoming is
reigniting debate over why the huge beasts became extinct.
Colorado paleontologist Robert Bakker, who led the team that found
the dinosaur remains, said Thursday the discoveries reinforce his theory that
dinosaurs became extinct gradually.
A scientist at the Smithsonian Institution who supports the theory
that dinosaurs met their end suddenly, in a cosmic collision, says the latest
finds prove nothing of the sort.
The extinction of dinosaurs is "a big area of controversy right now
in science," said Dr. Richard Stucky, paleontologist at the Denver Museum of
Scientists offer dozens of theories about the mysterious mass
extinctions, including a change in the Earth's motion, famine, parasites,
poisons, climatic changes, meteorites and even extraterrestrial hunters.
The debate is on again since Bakker's team of University of Colorado
scientists unearthed a 70-foot-long, 25-foot-high Haplocanthosaurus. A member
of the cetiosaur or "whale dinosaur" family. The "Carlin Giant" found near
McFadden, Wyo., was the largest cetiosaur ever located, Bakker said.
The second find is the only brontosaurus scientists have placed in
the Cretaceous Period, which began 135 million years ago.
Before that discovery, near Rock River, Wyo., in a fossil deposit
known as Breakfast Bench, no brontosaur had been found that was less than 137
million years old.
Bakker announced the discoveries Wednesday. The remains were found
"The fossil record clearly indicates that these mass extinctions were
not the result of a Saturday night of cosmic mayhem," Bakker said. "The last
remains of different (dinosaur) families are strewn through millions of years
of rock," he said.
Nicholaus Hotton, a curator of paleobiology at the Smithsonian
Institution, disagrees. He still subscribes to a collision theory, which he
said is evidenced by iridium-rich sediments in the deposits marking the end
of the Cretaceous Period. Iridium is a heavy metal found in platinum ores.
"The crustal rocks in the top kilometers of the earth are very poor
in iridium, but meteors and things are very rich in iridium. So why do you
find that in that zone?" Hotton said.
"The argument is that they were brought in from the outside ... an
asteroid, comet, or one hell of a big meteorite that struck the Earth. And in
doing so it disrupted the ecology," he said.
Bakker believes extensive migration and subsequent disease epidemics
may have wiped out dinosaurs. He said Hotton is missing the "frog facts."
"If a comet or asteroid hit the earth and killed all the dinosaurs,
how then were the deaths so selective?" he asked. "The fact (is) that the
little delicate animals -- like frogs -- survived and the large aggressive
According to Bakker, dinosaurs became extinct because of worldwide
diseases. "Dinosaurs didn't go out with a bang, they went out with worldwide
diarrhea," he said.
The cetiosaur bones eventually will be displayed at the University of
Wyoming and at North Carolina State University, which assisted the fieldwork.