Gaseous emissions from giant herbivores may have been enough to warm the Earth.
Sauropods included some of the largest animals to have ever lived on land such as the Brachiosaurus, Diplodocus and Apatosaurus. They lived during the Mesozoic era, when the Earth was typically much warmer and wetter than it is today — a characteristic that scientists have linked to the gaseous emissions produced by these enormous herbivores.
The greenhouse gas methane is a natural by-product of the digestive process of plant eaters, especially in herbivores called ruminants (Ruminantia) such as cows. According to the Australian Government National Greenhouse Gas Inventory, Australia’s livestock industry (including dairy) produces 10.2 per cent of Australia’s total greenhouse gas emissions.
Researchers suspect that, like ruminants, sauropods would have harboured methane-producing bacteria in their intestines to help digest fibrous foods. Published in the journal Current Biology, the study was conducted by David Wilkinson, of Liverpool John Moores University, and scientists at the University of London and the University of Glasgow.
“A simple mathematical model suggests that the microbes living in sauropod dinosaurs may have produced enough methane to have an important effect on the Mesozoic climate,” Dave Wilkinson of Liverpool John Moores University said.
By comparing these sauropods’ digestive systems with those of cows, the researchers conclude that the massive herbivores alone would have contributed as much as 520,000 million kilograms of greenhouse gasses to the Mesozoic atmosphere. When you compare that to current levels of methane output — all up about 500,000 million kilograms a year — the researchers believe that the gas had a significant affect on the warming of the planet.
Researchers warn that their answers are only estimates, as there is no way to tell what kind of bacteria lived in the digestive systems of these dinosaurs or what gasses they produced. However, Wilkinson thinks they would have produced methane like today’s animals.
“To process that amount of vegetation they have to be relying on microbes in their digestive system,” Wilkinson told LiveScience. “But without a time machine you can’t be sure.”