Aussie dinos hid underground to survive extreme cold and predators

September 28th, 2009 - 5:04 pm ICT by ANI  

Washington, September 28 (ANI): A new study has determined that some species of Australian dinosaurs has to take refuge underground to survive freezing temperatures and huge predators.

According to a report in Discovery News, the findings, which will be presented at next month’s Geological Society of America annual meeting, reveal how dinosaurs and certain other animals developed strategies for surviving harsh environments and predation.

Predator tracks previously found in Australia indicate that 770-kilogram carnivorous beasts hunted diminutive 10-kilogram dinosaurs, which had to think fast.

“What defense did they have other than running? How about staying out of sight in burrows?” said Dr Anthony Martin, a senior lecturer in environmental studies at Emory University and an honorary research associate at Melbourne’s Monash University.

In 2006, he identified the 95-million-year-old skeletal remains of a small adult dinosaur and two juveniles in a fossilized burrow in southwestern Montana.

The species is now called Oryctodromeus cubicularis, meaning “digging runner of the lair.”

That same year, he also found tracks for a carnivorous dinosaur, where a theropod (two-footed dinosaur) claw and a few related bones have been uncovered.

In 2007, while hiking in Victoria, Martin spotted three dinosaur burrows etched into a 105-million-year-old outcrop that’s about two metres long and 30 centimetres in diameter.

At least one of the burrows descends into a spiral and ends in an enlarged chamber.

“The burrows show a behaviour that was probably related to surviving a polar winter, but also could have served as protection against large predators, such as the large theropod dinosaurs,” Martin said, adding that Australia’s big Allosaurus-like dinosaurs “must have had some physiological adaptations that helped them to survive cold, dark winters.”

The average annual temperature in Early Cretaceous Victoria was likely less than -40 degree Celsius, “which means that wintertime temperatures were well below freezing, plus it was dark for five to six months of the year,” he said.

More recently, Martin has found insect and crayfish fossil burrows in Victoria that date back to the same period.

The crayfish burrows are the oldest known for Australia.

Mammal and turtle fossils suggest these animals might also have retreated into underground chambers.

Taken together, Martin said, the “dinosaur burrows and tracks, as well as crayfish and insect burrows, give us new insights on animals’ adaptations to polar environments during the time of the dinosaurs.” (ANI)

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