Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

T. rex had teen pregnancies

15.01.2008
Dinosaurs grew fast, reached sexual maturity early and died young

Dinosaurs had pregnancies as early as age 8, far before they reached their maximum adult size, a new study finds.

Researchers at Ohio University and University of California at Berkeley have found medullary bone – the same tissue that allows birds to develop eggshells – in two new dinosaur specimens: the meat-eater Allosaurus and the plant-eater Tenontosaurus. It’s also been found in Tyrannosaurus rex.

The discovery allowed researchers to pinpoint the age of these pregnant dinosaurs, which were 8, 10 and 18. That suggests that the creatures reached sexual maturity earlier than previously thought, according to the scientists, who will publish their study Jan. 15 in the journal Proceedings of the National Academy of Sciences.

The scientists originally studied the bones, which come from different geologic periods, to learn more about dinosaur growth rates. Because researchers rarely find fossils of adult dinosaurs, some have speculated that the ancient beasts never stopped developing, said Andrew Lee, a postdoctoral student at the Ohio University College of Osteopathic Medicine who conducted the work as a graduate student at University of California at Berkeley with scientist Sarah Werning.

The new study suggests another explanation: Dinosaurs grew fast but only lived three to four years in adulthood. Offspring were probably precocious, like calves or foals, Lee said.

“We were lucky to find these female fossils,” Werning said. “Medullary bone is only around for three to four weeks in females who are reproductively mature, so you’d have to cut up a lot of dinosaur bones to have a good chance of finding this.”

The research also offers more evidence that dinosaurs were less like reptiles and more like birds. Though dinosaurs had offspring before adulthood, their early sexual maturity was more a function of their tremendous size than any anatomical similarity to crocodiles.

When they factored in the size of the dinosaurs, Lee and Werning found that the reptile model for sexual maturity predicted that the ancient beasts would have had offspring as late as age 218. “That’s clearly ridiculous,” Lee said. Research shows that most dinosaurs only lived until age 30, though long-necked creatures such as Brontosaurus may have reached 60.

“We hope this is the last nail in the coffin, but some scientists still cling to the notion that dinosaurs weren’t like birds,” Lee said.

The discovery also sheds new light on the evolution of birds. The presence of medullary tissue in these dinosaurs, which lived as long as 200 million years ago, shows that the reproductive strategies of modern birds have ancient origins.

Because birds have evolved to be much smaller than dinosaurs, however, their reproductive strategies and growth spans now bear no resemblance to those of T. rex. Birds grow to adulthood in only 40 days, but may take one to 10 years to reach sexual maturity. That’s relatively similar in other tiny critters such as shrews, Lee said.

Andrea Gibson | EurekAlert!
Further information:
http://www.ohio.edu

More articles from Studies and Analyses:

nachricht Researchers simplify tiny structures' construction drip by drip
12.11.2018 | Princeton University, Engineering School

nachricht Mandibular movement monitoring may help improve oral sleep apnea devices
06.11.2018 | Elsevier

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Nonstop Tranport of Cargo in Nanomachines

Max Planck researchers revel the nano-structure of molecular trains and the reason for smooth transport in cellular antennas.

Moving around, sensing the extracellular environment, and signaling to other cells are important for a cell to function properly. Responsible for those tasks...

Im Focus: UNH scientists help provide first-ever views of elusive energy explosion

Researchers at the University of New Hampshire have captured a difficult-to-view singular event involving "magnetic reconnection"--the process by which sparse particles and energy around Earth collide producing a quick but mighty explosion--in the Earth's magnetotail, the magnetic environment that trails behind the planet.

Magnetic reconnection has remained a bit of a mystery to scientists. They know it exists and have documented the effects that the energy explosions can...

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Optical Coherence Tomography: German-Japanese Research Alliance hosted Medical Imaging Conference

19.11.2018 | Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

 
Latest News

Nonstop Tranport of Cargo in Nanomachines

20.11.2018 | Life Sciences

Researchers find social cultures in chimpanzees

20.11.2018 | Life Sciences

When AI and optoelectronics meet: Researchers take control of light properties

20.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>