Why does a kangaroo expel less methane than a cow? Researchers from the University of Zurich and Australia decide to investigate – and discovered that the emission of this climate-damaging gas in kangaroos is linked to how long food is digested.
Animals produce methane during the digestion process – some more than others. Currently, around 20 percent of the world’s methane emissions stem from ruminants. If this gas is released into the atmosphere, it aggravates the greenhouse effect and aids global warming.
Previous studies revealed that ruminants, which include cows and sheep, release more methane into the environment than kangaroos, for instance – even though the latter also possess a foregut, where bacteria break down the plant fibers and produce methane (much like in a cow’s rumen).
Exactly why kangaroos produce less methane, however, remained a mystery. The belief was that a different intestinal flora composition to a cow’s was responsible.
Researchers from the University of Zurich, ETH Zurich and the University of Wollongong in Australia have now studied the previous assumptions from a different angle. The team measured how much methane kangaroos emit per food intake.
“If you consider the absolute volume of methane per body size, kangaroos produce about as much as horses or ostriches – i.e. significantly less than cows,” explains Marcus Clauss from the University of Zurich. “If the gas production is correlated with the amount of food ingested, however, the amount of methane is higher and therefore closer to the ruminants again. In other words, the digestion process itself in kangaroos is not all that different to a cow’s.”
Different conditions for bacteria
Moreover, the researchers discovered that the amount of methane per food intake can vary in the space of a few days. “If the animals eat less, i.e. the food remains in their foregut for longer and the bacteria have more time to digest, they produce more methane per food intake,” says Adam Munn from the University of Wollongong.
The researchers conclude that differences between species are more down to the conditions that the intestinal bacteria are exposed to than the exact type of these bacteria. Under normal conditions, kangaroos digest more rapidly than cows.
“If we want to reduce methane production in cows, the question is whether they can be bred so that parts of the food don’t remain in the rumen for as long,” say the researchers, who published their study within the scope of a project on methane production in wild animals that was funded by the Swiss National Science Foundation.
Vendl C, Clauss M, Stewart M, Leggett K, Hummel J, Kreuzer M, Munn A (2015) Decreasing methane yield with increasing food intake keeps daily methane emissions constant in two foregut fermenting marsupials, the western grey and red kangaroos. Journal of Experimental Biology (in press). November 4, 2015. Doi 10.1242/jeb.128165
Melanie Nyfeler | Universität Zürich
Global threat to primates concerns us all
19.01.2017 | Deutsches Primatenzentrum GmbH - Leibniz-Institut für Primatenforschung
Reducing household waste with less energy
18.01.2017 | FIZ Karlsruhe – Leibniz-Institut für Informationsinfrastruktur GmbH
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
20.01.2017 | Awards Funding
20.01.2017 | Materials Sciences
20.01.2017 | Life Sciences