Navigation Links
Size of mammals exploded after dinosaur extinction
Date:11/25/2010

Researchers demonstrate that the extinction of dinosaurs 65 million years ago made way for mammals to get bigger - about a thousand times bigger than they had been. The study, which is published in the prestigious journal Science, is the first to show this new pattern of increased body size of mammals after the exit of the dinosaurs.

"Basically, the dinosaurs disappear and all of a sudden there is nobody else eating the vegetation. That's an open food source and mammals start going for it, and it's more efficient to be an herbivore when you're big," says paper co-author Dr. Jessica Theodor, associate professor in the Department of Biological Sciences at the University of Calgary.

Theodor says as well as confirming the dramatic growth in mammalian size after the dinosaurs, the study shows that the ecosystem is able to reset itself relatively quickly.

"You lose dinosaurs 65 million years ago, and within 25 million years the system is reset to a new maximum for the animals that are there in terms of body size. That's actually a pretty short time frame, geologically speaking," she says. "That's really rapid evolution."

Theodor says mammals grew from a maximum of about 10 kilograms when they were sharing the earth with dinosaurs to a maximum of 17 tonnes afterwards.

"Nobody has ever demonstrated that this pattern is really there. People have talked about it but nobody has ever gone back and done the math," says Theodor one of the 20 researchers from around the world who worked on the study. "We went through every time period and said OK, for this group of mammals what's the biggest one? And then we estimated its body mass."

In order to document how big mammals grew after the 'competitive release' caused by the extinction of dinosaurs, researchers collected data on the maximum size for major groups of land mammals on each continent, including Perissodactyla, odd-toed ungulates such as horses and rhinos; Proboscidea, which includes elephants, mammoth and mastodon; Xenarthra, the anteaters, tree sloths, and armadillos; as well as a number of other extinct groups.

The results give clues as to what sets the limits on mammal size on land; the amount of space available to each animal and the climate they live in. The colder the climate, the bigger the mammals seem to get, as bigger animals conserve heat better. It also shows that no one group of mammals dominates the largest size class the absolute largest mammal belongs to different groups over time and space.


'/>"/>

Contact: Leanne Yohemas
leanne.yohemas@ucalgary.ca
403-220-5144
University of Calgary
Source:Eurekalert  

Related biology news :

1. Dinosaur-chewing mammals leave behind oldest known tooth marks
2. Carnivorous mammals track fruit abundance
3. Small mammals -- and rest of food chain -- at greater risk from global warming than thought
4. Large mammals need protected areas, forest cover in India
5. Tree-dwelling mammals climb to the heights of longevity
6. Researchers use new acoustic tools to study marine mammals and fish
7. Study shows loss of 15-42 percent of mammals in North America
8. Climate-caused biodiversity booms and busts in ancient plants and mammals
9. After dinosaurs, mammals rise but their genomes get smaller
10. CU-Boulder study shows 53 million-year-old high Arctic mammals wintered in darkness
11. Climate change driving Michigan mammals north
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Size of mammals exploded after dinosaur extinction
(Date:2/5/2016)... , Feb. 5, 2016 ... of the "Global Facial Recognition Market ... --> http://www.researchandmarkets.com/research/5kvw8m/global_facial ) has announced the ... Market 2016-2020" report to their offering. ... http://www.researchandmarkets.com/research/5kvw8m/global_facial ) has announced the addition of ...
(Date:2/3/2016)... 3, 2016 Vigilant Solutions announces today that ... Missouri solved two recent hit-and-run ... data from Vigilant Solutions. Brian Wenberg ... the victim was walking out of a convenience store and witnessed an elderly ... his vehicle, striking his vehicle and leaving the scene.  ...
(Date:2/2/2016)... Feb. 2, 2016 Checkpoint Inhibitors for ... Market Are you interested in the future ... for checkpoint inhibitors. Visiongain,s report gives those predictions ... and national level. Avoid falling behind in ... opportunities and revenues those emerging cancer therapies can ...
Breaking Biology News(10 mins):
(Date:2/10/2016)... ... 10, 2016 , ... Benchmark Research, a fully-integrated network of ... long-standing principal investigators (PI) to the roles of Chief Medical Officer, Clinical Research ... Laurence Chu, a Benchmark Research PI in the Austin office, will assume the ...
(Date:2/10/2016)... ... February 10, 2016 , ... PatientCrossroads announces that ... secure online PatientCrossroads platform, has exceeded both its one-year and overall recruitment goals ... study, which seeks to advance understanding of the hereditary risks for certain kinds ...
(Date:2/10/2016)... ... February 09, 2016 , ... Creation ... winner of the Highest Overall Customer Rating Award from Circuits Assembly , today ... units across the USA, Canada, Mexico and China. , The EMS provider, known ...
(Date:2/9/2016)... ... February 08, 2016 , ... Net-Translators, ... today the launch of its revamped and improved website. In an on-going effort ... the redesigned website will better communicate how the company designs and delivers thorough, ...
Breaking Biology Technology: