Camels are frugal methane emitters

Camels do not eat enough to emit methane that could challenge the levels reached by cattle and sheep
Image: By Keven Law via Wikimedia Commons

FOR IMMEDIATE RELEASE Some domesticated animals add appreciably to the methane which is warming the atmosphere.  But despite earlier assumptions, camels are not among them. LONDON, 10 April – Never accuse science of neglecting the smallest and apparently least significant detail in its efforts to understand fully how the Earth and all that’s in it keeps going. One of the latest arcane revelations comes from scientists in Switzerland, who describe in the Public Library of Science journal PLOS One why we should not heap blame on camels for adding to the methane already in the atmosphere. Camels – and their camelid relatives, llamas, guanacos, alpacas, vicuñas, dromedaries and Bactrian camels – do produce methane, which is more than 20 times as potent a greenhouse gas as carbon dioxide. But they produce significantly less of it than ruminants like cattle, sheep and goats. When they are digesting their food, ruminants exhale large quantities of methane, around 20% of global methane emissions. So far the assumption has been that camels, with their similar digestive systems, produce the same amount of the gas.

Smaller appetites

But now researchers at the University of Zurich and ETH Zurich have shown that camels release less methane than ruminants. Ruminants and camelids are similar but not identical: both groups have stomachs with several chambers, enabling them to regurgitate food from one chamber in order to reduce it in size by renewed chewing. That is why people had assumed till now that camelids and ruminants produce similar amounts of methane. But the researchers have concluded that in absolute terms camels release less methane than cows and sheep of comparable body size. Admittedly, it is slightly more complicated than that: if you compare methane production with the amount of what the team calls “converted feed”, then methane releases are the same in both groups. But the amount of converted feed is what matters. The research may be less esoteric than it at first appears. Working with Zurich zoo and private camel keepers, the researchers measured methane production in three types of camelids. They found that all three had a lower metabolism than ruminants – because they eat less.

Not enough meat

One of the report’s authors, Dr Marcus Clauss, a veterinary surgeon from the Vetsuisse Faculty of the University of Zurich, told the Network: “For each unit of digested food, ruminants and camelids produce the same amount of methane. “But camels generally have a lower metabolism and hence eat less than domestic ruminants. So the total amount of digested fibre per day is lower in camelids, hence the total amount of methane produced is also lower.” The authors say the camelids’ lower metabolism may be important for countries with lots of camels, like the dromedaries of the Middle East and Australia, or the alpacas and llamas of South America. But they do not advocate a switch from beef and lamb to camel meat. Dr Clauss says: “Personally, I do not think this has relevance to agricultural systems, because there are many other things to consider. For example, I am sure you could not produce the same amount of meat in the same time from a camel as you can from a steer.” – Climate News Network