"Kangaroo: It’s What’s for Dinner"
Written by Cody Gillin | Photos by Sita Thompson



Imagine sitting in Bob’s Burgers and Brew, ready to bite into an American classic: the hamburger.

Now picture the braised beef patty being replaced with grilled kangaroo. Sound far-fetched? Scientists in Australia don’t think so. In fact, they believe putting kangaroo on the menu could help save the planet.

Recently, scientists have been raising a stink about cow farts. More specifically, they’re looking at one component of cow flatulence: methane. Methane is a greenhouse gas, one of many gases that hang around in the atmosphere, trap heat and cause global temperatures to rise. According to the United States Environmental Protection Agency, cows, sheep and other livestock are responsible for 28 percent of methane emissions from human-related activities around the world.

But kangaroos don’t have a gas problem – they don’t produce methane. In Australia, researchers are looking to kangaroos as a means of reducing methane emissions to help curb global climate change.

Herbivores are animals that eat plants. But they don’t actually digest plant material on their own. Instead, a bunch of microbes do it for them. When a cow swallows grass, the grass travels down the esophagus to a chamber called the rumen. This place is home to bacteria that break down the grass through fermentation. Cows get their energy by metabolizing this plant material.

After the microbes have fermented all the grass in the rumen, they pass into the stomach and are digested. Cows get their proteins by digesting their own grass-fermenting bacteria, according to the United States Department of Agriculture.

This is a pretty good system. There’s just one little problem: during fermentation, hydrogen is formed. If it’s not removed, it can slow the whole process. In cows and sheep, the fermenting microbes get rid of hydrogen by making methane.

But not all herbivores produce methane. Kangaroos have a different fermentation chamber, called the foregut, filled with a different set of bacteria. Instead of using excess hydrogen to make methane, kangaroo microbes make acetic acid, which the kangaroos absorb and use for energy.

Dr. George Wilson, principal of Australian Wildlife Services, co-authored a 2008 study comparing environmental impacts of kangaroos and livestock. He suggests replacing cows and sheep with kangaroos as one of Australia’s primary meat sources could mitigate global warming.

"If you increase kangaroo populations and reduce sheep and cattle, then you can eliminate some of the methane emissions from the livestock industry," said Wilson.

Australia’s ranges are home to about 7.5 million cattle and 38.7 million sheep. Wilson proposed eliminating 7 million cattle and 36 million sheep over the next 12 years could reduce annual greenhouse gas emissions from Australian agriculture by about 20 percent.

Drawing down the numbers of sheep and cattle would create a lot of space suitable for kangaroos. Habitat for many more kangaroos is an important part of Wilson’s model, because it would take a lot of kangaroos to replace the meat lost from reducing sheep and cattle herds.

Right now there are about 34 million kangaroos on the Australian rangelands. Wilson’s study projected that 175 million kangaroos would be needed to produce the same amount of meat as the current livestock population. If all those kangaroos were lined up from head to tail, they would wrap around the earth 10 times.

Besides reducing methane emissions, there are other benefits of replacing range livestock with kangaroos. According to Dr. Ian Hume, wildlife nutrition specialist and professor emeritus at the University of Sydney, sheep and cattle are responsible for extensive environmental degradation. Livestock have hard hooves that erode soils, especially near water. Soft-footed kangaroos don’t do this kind of damage.

Kangaroos living on golf courses is a specific example of their low environmental impact, Wilson said.

"You wouldn’t find anyone who would let a bunch of sheep and cattle out there, but many golf courses have 50, 60, maybe 70 wild kangaroos."

So are Australians willing to replace their moo-burgers with roo-burgers?

According to Peter Ampt, program manager for Future of Australia’s Threatened Ecosystems and author of a recent study on consumer reactions to kangaroo meat, most people like kangaroo meat flavor. While it can be described as gamey, much like deer or llama, it generally has a mild and pleasant taste.

Ampt said that eating kangaroo offers a variety of incentives. Kangaroo meat is lower in fat than both beef and lamb. The roo industry would also create a stable job market for many indigenous Australians in the isolated outback.

But some consumers have beef with the kangaroo harvest. Kangaroos are nocturnal, and the most efficient way to harvest the animals is to shoot them in the field at night using spotlights and rifles. Although the Australian government regulates the process, some people see it as cruel.

Others just don’t like the thought of eating the meat.

"Rural people have traditionally shot roos for dog food," Ampt said, "So they will always associate the smell with that."

Wilson and Hume agreed that taking full advantage of the environmental benefits of kangaroos for lower-emission meat would require cultural and social changes.

"It’s not going to be an overnight switch," Hume said. "There is a negative feeling about eating the national symbol, and consumers need to be educated."

Not everyone sees kangaroo as the eco-friendly entrée of the 21st Century.

"Some people have come up with the ridiculous notion that eating Australian native wildlife is somehow green, wholesome, and good for the planet," said Malcolm Fisher, community campaigner for The Wilderness Society, an environmental protection organization.

In a recent letter submitted to the Australian Federal Minister for the Environment, The Wilderness Society said there are many problems associated with the kangaroo industry. Kangaroos are marsupials, meaning females carry their young in a pouch during initial development. A large number of mothers carrying joeys (baby kangaroos) are harvested each year, killing two generations at once.

The Wilderness Society also maintains that the existing kangaroo industry can’t sustain current growth. The Society said one industry leader wants kangaroo meat to represent 8 percent of all meat consumption in Australia by 2010. To achieve this goal, all export markets would need to be closed and kangaroo harvest quotas increased by 78 percent.

Not to be forgotten are the livestock ranchers, who make a living from the industry some scientists propose to diminish. How do they feel about replacing cows with kangaroos?

"Suggestions that kangaroos could replace cattle and sheep for meat production in Australia’s rangelands is quite simply not a realistic option," said Jed Matz, policy director for the Cattle Council of Australia.

According to Matz, the Australian beef industry exports around two-thirds of its production to more than 100 countries. The Council isn’t opposed to kangaroo meat production. But their global consumers demand beef – not kangaroo – and collectively purchase about $120 million worth of beef products each week.

If the global economy wants Australian beef, can anything be done to supply the demand without the associated methane emissions? Dr. Athol Klieve, senior researcher with the Queensland State Department of Primary Industries and Fisheries, wants to find out if he can make a methane-free cow. He hopes to transfer some of the kangaroo’s digestive organisms into livestock.

But you can’t just take kangaroo microbes, toss them into cows and sheep and expect the livestock to stop producing methane. Fermenting chambers are like big factories where each type of bacteria has a different job to do. The host of bacteria inside kangaroos works differently than the bacteria inside cows. Before they can put kangaroo microbes into a cow’s stomach, scientists must first find out how each strain of bacteria does its job.

Klieve and his colleagues have isolated a number of species of bacteria that make acetic acid in kangaroos. It is those microbes that he hopes to move to sheep and cattle. But it may be years before science engineers a climate-friendly cow.

"We are trying to gather knowledge and a relatively complete understanding of how a very complex and unexplored ecosystem works," Klieve said. "This all takes time and involves the use of molecular techniques that are very complex and in many cases still evolving themselves."

While concepts seem laudable, the reality of transforming the livestock industry in Australia is complicated. Many practical, ethical and economic questions must be considered. Are the emission-cutting proposals achievable? Will the kangaroo industry be humane? Can the market change and still meet global demands?

For a few scientists trying to get the Australian cattle industry to go green, the future is promising. Whether it’s convincing the public to eat more kangaroo steaks or biologically engineering a methane-free cow, researchers from Down Under are going over the top to reduce methane emissions from livestock and get serious about global climate change.

A Local Solution to Cow Pollution: the Straight Poop on Manure

As Australia turns to kangaroos to eliminate the environmental problems associated with raising livestock, here in northwest Washington, farmers are taking a different approach.

Whatcom County is home to about 50,000 cows, said Paul Grey, executive director of Whatcom Farm Friends. That’s about one cow for every three residents. But the local bovines aren’t destined for the barbecue like their Aussie cousins. They’re dairy cows, and they live to produce the stuff that muscular Mr. T. told kids to drink: milk.

While busy making milk, Whatcom cows also produce methane. But unlike Aussie cattle, whose global warming contribution is primarily from flatulence, dairy cows have a more pressing poop predicament.

On the range, cows do their business sporadically across the land. Manure is rapidly aerated and dehydrated, reducing the production of methane.

At a dairy, the livestock are kept in close proximity. All those cows together make a lot of manure, and after a while the puckies pile up. Farmers collect the manure and deposit it in reservoirs, where it slowly decomposes.

When all that manure is put together, it continues to ferment and produce methane. The process emits foul smelling gasses like ammonia and volatile organic compounds. It also releases nitrogen and phosphorus. If these nutrients leech into water sources, they can cause harmful algal blooms, loss of aquatic plants and fish mortality.

Enter the anaerobic digester at the Vander Haak dairy farm in Lynden. This house-sized machine takes biological wastes in one end, and sends electricity and useable substances out the other.

Mike Apol is regional manager of the Biogas/Renewable Energy program for Andgar, the company that makes the digester in Lynden. He said the machine simply finishes the process started inside the cows. Organic products such as manure and feed waste enter the digester. The material is heated to 100 degrees Fahrenheit. Over a period of about three weeks, it passes through several chambers, constantly being mixed for maximum fermentation.

Methane collects on top of the churning biowaste. It fuels the engine of a gas-combustion generator that sends electricity directly into the power grid. The dairy produces 425 kilowatt-hours of energy each day. That’s enough to meet the energy demands of 16 single-family homes every month.

One of the byproducts of the whole process is a mostly inorganic liquid that can be sold as a fertilizer.

"They tested it on the grass in the field next to the digester," Apol said. "Grass on the fertilized side was much more thick and green than the part they left alone."

The second byproduct is an organic solid. The Vander Haak dairy utilizes it as bedding in cow stalls instead of buying sawdust.

When it comes to solving the problems with poop, dairies using anaerobic digesters such as the Vander Haak farm in Lynden are in a unique position to handle manure-related environmental concerns.

For more information on the Vander Haak dairy and anaerobic digester, see "Manure-able Energy" in The Planet, Winter 2005.

Cody Gillin studies environmental science. This is his first published piece.