by Olivia Holston with Nicole Ames

Kangaroos are quite graceful hoppers and a beautiful sight—until one ends up hopping around your living room.  In his article in The Huffington Post, McGuirk (2009) mentions an Australian family who experienced just that.  The animal frantically jumped through a bedroom window and hopped around the house in a frenzy until it was shooed out the front door (¶ 4).  It is clear that this is not normal behavior for a wild animal, but rather the result of excessive numbers of kangaroos, but in New South Wales, Australia, kangaroos increasingly crowd areas not typically occupied by wild animals.  As an Animal Science major at the University of Massachusetts Amherst, I have consulted the relevant literature concerning this issue.  Here I will argue that if Australia manages its kangaroo population properly, it can also dramatically decrease its greenhouse gas emissions while helping to keep humans safe and ensuring a sustainable environment, for kangaroos and other animals.

Breeding Machines

Kangaroos are impressive animals; not only do they use hopping as their main source of movement, but they also reproduce very rapidly.  Marsupials in general have mastered the art of efficient reproduction and kangaroos are no exception.  A baby kangaroo, known as a joey, “emerges after only 33 days” inside its mother’s womb (“Kangaroo,” 2010, ¶ 24).  Only the size of a lima bean, it climbs into its mother’s pouch and attaches to a teat.  Once there, the joey continues to develop and “eventually, after ca. 235 days, it leaves the pouch for the last time” (“Kangaroo,” 2010, ¶ 24).  While one joey is developing in the pouch, the mother can have a fetus growing in her womb, along with another embryo ready and waiting inside of her.  Thus, female kangaroos can theoretically be – and usually are – constantly pregnant, which greatly contributes to the massive populations.  In support of this, the webpage of the Australian Government Department of Foreign Affairs and Trade (DFAT) states that “because they are such prolific breeders, a kangaroo population can increase fourfold in five years if it has continuous access to plentiful food and water” (DFAT, 2010, ¶ 7).

The kangaroo, Australia’s beloved national emblem, seems to be taking over the continent.  An article in Australian Geographic (2004) sited “[a] 1995 survey of…Tidbinbilla Nature Reserve in the Australian Capital Territory [which] revealed…the reserve’s density of grey kangaroos had reached a staggering 357 animals per square kilometer” (Reardon, ¶ 1).  A 2007 article by the Associated Press on MSNBC online stated the population “on the outskirts of Canberra…[reached] 1,100 kangaroos per square mile – the densest population ever measured in the region” (Associated Press, 2007, ¶ 2).

As populations reach such high levels, the kangaroos themselves are affected along with other innocent bystanders.  According to an article on The Huffington Post, kangaroos pose an immediate and obvious threat to humans.  In addition to occasionally hopping through residential homes, kangaroos also cause massive amounts of traffic accidents according to McGuirk (2009).  In areas of gross overpopulation, kangaroos also pose a threat to sheep and cattle farmers.  A kangaroo’s diet consists mainly of grasses, therefore, they seriously deplete the pastures originally intended to feed the sheep and cattle raised by farmers.  As cited in an Australian Geographic (2004) article, when “[a]sked to reckon kangaroo-induced losses, 906 farmers and graziers across five pastoral zones arrived at a figure of $113 million — half of it due to lost forage” (Reardon, ¶ 26).  Not only does this uncontrolled grazing have a great effect on the biodiversity of grasslands, but it also has long term effects on endangered insects and lizards in the area.  McGuirk (2009) explains that many rare insects and lizards rely on tall, brushy grasses for food and shelter and once the kangaroos deplete these grasses, the endangered species’ struggle for survival will become even more difficult.  Reardon (2004) describes the idea that unmanaged kangaroo populations pose a threat to the kangaroos themselves.  Juvenile kangaroos typically become emaciated because they cannot compete with the elders for food.  So as kangaroo populations increase, not only are kangaroos starving themselves, but they are also causing damage to pastures, endangered species’ habitats, and grassland biodiversity.

Population Management

Something must be done about this situation for the protection of humans, endangered species, and kangaroos themselves.  Fortunately, as detailed on the Department of Environment and Conservation (DEC) NSW webpage (2006), the Commonwealth Minister for the Environment and Heritage approved the New South Wales Commercial Kangaroo Harvest Management Plan as an official Wildlife Trade Management Plan on December 19, 2006.

The Kangaroo Management Plan (KMP) is an extensive, well thought-out plan aimed at controlling the vast kangaroo populations in the area of New South Wales, Australia.  The DEC webpage (2006) contains an electronic copy of the  plan, which can be viewed by the public.  The KMP is valid from January 1, 2007 to December 31, 2011 and allows the commercial harvest of four kangaroo species under certain restrictions.  The DEC (2006) states the primary goal of the KMP is:

[T]o ensure that the commercial harvest of kangaroos is ecologically sustainable.  This will be achieved through the application of the best available scientific knowledge, best practice   management and monitoring of outcomes to ensure the viability of kangaroo populations is not compromised by any action undertaken in accordance with this plan. (p.6)

The KMP also details the extensive limitations that are put on kangaroo harvest in this area.  Kangaroo culling is only permitted in designated zones, which do not include reservation areas.  Also, in order to harvest the kangaroos in these areas, people must obtain a variety of licenses which permit them to harvest a limited number of kangaroos in a designated zone and sell them only to licensed dealers.  Extensive attention is given to these licenses and each license holder is subject to the rules and regulations set forth by the KMP (Department of Environment and Conservation, 2006).

The KMP is so well thought out and sustainable that kangaroo populations remain at the same levels as they did four years ago.  According to the commercial take reports published by the Department of Environment, Climate Change, and Water (2010), the total populations of all four kangaroo species totaled over five and a half million in 2006 and more than eight hundred thousand kangaroos were culled just that year.  By the end of 2009, three full years into the management plan, the population remained just as high (Department of Environment, Climate Change, and Water, 2010).  I think it is fair to say that the KMP is certainly staying true to its ecological sustainability clause; however, farmers are most likely still losing their pastures due to kangaroo grazing and humans are still being plagued by the high levels of kangaroos in their communities.  Not to mention the extreme effect kangaroos are having on the biodiversity of grasslands and the lives of endangered species.  Thus, I believe the KMP is going to be needed long past December 31, 2011 in order to prevent kangaroo populations from rising again.

Kangaroos’ Good Side

Although kangaroos are presently causing several problems in Australia, they do have many redeeming qualities, one of which being their digestive systems.   Kreuder (2004), a faculty member of Iowa State University, wrote an essay comparing the digestive anatomy of ruminants and marsupials.  In this essay, she details the kangaroo digestive system, which consists of a large stomach with multiple sacs, allowing them to consume a wide variety of forages and utilize the energy from them (¶ 15).  Kangaroos, similar to the sheep and cattle I have learned about in my studies, ferment the foods they eat, meaning microorganisms living in their stomachs break down foodstuffs that would otherwise be unavailable for the animal’s nutrition.

Therefore, animals that ferment food in their stomach can consume primarily forages that would otherwise provide no nutrition.  Kreuder (2004) explains that sheep and cattle have unique microbes in their stomachs that produce large amounts of methane gas through the process of fermentation, which is primarily released into the atmosphere when the animal belches (¶ 18).  According to Kreuder (2004), “methane production is an unnecessary waste product and leads to decreased feed efficiency and loss of metabolizable energy” (¶ 21).  Not only does methane create an energy loss for ruminant animals, but it also wreaks havoc on the environment.  A New Scientist article in 2004 stated methane “gas is a potent source of global warming because, volume for volume, it traps 23 times as much heat as the more plentiful carbon dioxide” (¶ 2).  So while sheep, cattle, and other ruminants seem harmless, they are major contributors to global warming due to the large release of methane, an end product of fermentation.

A Science Daily article titled “Fry Me Kangaroo Brown, Sport” (2008) stated “[k]angaroos emit one-third as much methane as ruminant animals, such as cattle, sheep and goats, which are responsible for 60 percent of global methane emissions” (¶ 7).  According to Kreuder (2004), the stomachs of kangaroos contain a different variety of microorganisms, some of which convert methane into acetate which can then be used for further energy (¶ 21).  Thus, kangaroos are very useful creatures; they consume inexpensive and otherwise useless foods and they play a limited role in global warming compared to other agricultural animals.

The Solution

On the whole, kangaroos are extremely efficient breeders and their impact on the atmosphere is much less than that of other agricultural animals.  Why not use these two qualities of the kangaroo to slow global warming?  The solution is simple to me, abandon the sheep and cattle farming and switch to a primarily kangaroo meat market.  The Australian Government DFAT (2008) recognizes that kangaroo meat is not only popular with Australian natives, but it is also exported to an estimated fifty-five countries worldwide (¶ 19).  The Australian Government DFAT (2008) webpage also explains that, kangaroo meat’s “growing appeal stems from its well-flavoured, slightly gamey taste…[k]angaroo meat contains very little saturated fat relative to other meat and is high in protein, zinc, and iron” (¶ 19).  As kangaroo meat gains popularity it will become increasing accessible and, until then, it can be purchased from websites such as exoticmeats.com or adventureinfood.com based in the United States.  If people knew they could simply eat kangaroo instead of beef in order to help fight global warming, I believe kangaroo meat would become an extremely popular menu item.

Ideally, Australian farmers would be given incentives to shut down their sheep and cattle productions and focus on kangaroos.  The farmers would not own the kangaroos, nor would they be held captive, as I believe this would cause ethical concern and would detract from the kangaroos’ quality of life.  Instead, farmers should cultivate lands to support the kangaroo populations and then harvest them in the same way the Kangaroo Management Plan currently does.

Overall, I think Australians should use their natural resources, such as the kangaroo, to help fight global warming.  “Fry me Kangaroo Brown, Sport” (2008) supports the idea of a switch to kangaroo markets and states that, if that switch is made, Australia “would lower greenhouse gas emissions by [at least] 16 megatonnes, or 3 percent of Australia’s total emissions” (¶ 1).  So I say buy some kangaroo meat, fire up the grill, and get ready to enjoy a healthy and delicious meal – the planet will thank you later.

References

Associated Press. (2007, May 14). Australia officials want to kill 3,000 kangaroos. MSNBC. Retrieved from msnbc.msn.com

Australian Government DFAT (Department of Foreign Affairs and Trade). (2008). About Australia: Kangaroos. Retrieved from http://www.dfat.gov.au

Department of Environment and Conservation NSW. (2006). New South Wales commercial kangaroo harvest management plan 2007-2011 [Government Document]. Sydney, Australia. Retrieved from www.environment.nsw.gov.au

Department of Environment, Climate Change, and Water NSW. (2010). Tag allocations and commercial take reports. Retrieved from www.environment.nsw.gov.au

“Fry Me Kangaroo Brown, Sport.” (2008, August 11). Science Daily. Retrieved from www.sciencedaily.com

Kangaroo. (2010). Wikipedia: the free encyclopedia. Retrieved from en.wikipedia.org

Kreuder, A. (2004, April 14). Comparison of digestive system adaptations of placental ruminants and the herbivorous marsupials of Australia. Iowa State University. Retrieved from www.biology.iastate.edu

McGuirk, R. (2009, March 17). Kangaroos in the firing line in Australia. The Huffington Post. Retrieved from www.huffingtonpost.com

Reardon, M. (2004). Too many roos? Australian Geographic, (73), 86-97.

Saving earth from sheep burps. (2004). New Scientist, 183(2466), 18.