Population Control Controversy
Enhanced Video Resource

This video resource explores the controversy over the Australian government’s approach to controlling the growing population of kangaroos in Canberra through culling.

Discussion Questions:

  • How can the cull be considered an example of a practice that is “cruel to be kind”?
  • Can culling be done humanely?  Defend your answer.
  • What are the limitations to the humane practices of kangaroo sanctuaries and contraception?
  • What do you think the best solution is to the surging kangaroo population: the cull, kangaroo sanctuaries or contraception? Explain your rationale.
  • Is it wrong to kill an animal that has become part of the Australian identity?  Why or why not?

Background Essay:

The kangaroo is one of Australia’s most iconic animals, but their growing numbers have resulted in a controversy of epic proportions. In the last 50 years the kangaroo population in the Australian capital city of Canberra has exploded from a few hundred to tens of thousands, thusly earning the moniker “Urban Kangaroos.”

The area surrounding Canberra has been in a drought for the past 15 years. As a result, eastern gray kangaroos have been forced from their natural habitat in the hills above the city into suburban lawns and urban parks to graze on grass. Further exacerbating the situation is urban development and a lack of predation.  Urban expansion has resulted in land clearing that provides open pastures for grazing. Additionally, population control has all but wiped out the kangaroos’ natural predator, the dingo.

Overgrazing reduces grassy fields to dust and destroys the natural habitat of a number of endangered species, including the grassland earless dragon, the striped legless lizard, and the golden sun moth. With the kangaroo numbers continuing to grow, the government solution has been to reduce the population though culling, a process that is conducted under the strict environmental controls provided by the Australian Government’s Environment Protection and Biodiversity Conservation Act of 1999. The cull is carried out by experienced marksmen who shoot adult kangaroos in the head, while crushing or decapitating the young joeys. Media coverage and protest groups have brought a great deal of attention to this government practice and have prompted a national debate over the appropriateness of the cull.

The heated debate is leading many scientists to look for more humane and efficient solutions to the surging population that is currently damaging the ecosystem. One alternative is to move a portion of the kangaroos from overpopulated areas to dedicated sanctuaries that can easily accommodate them. Scientists have captured, rehabilitated, and released injured kangaroos into protected areas where the kangaroos can live in their natural habitat without threat or intrusion. Critics of this solution believe there are far too many kangaroos to safely and economically capture and release a large enough number to have a positive impact on the ecosystem. Scientists are also researching methods to limit the reproduction of kangaroos. The research is aimed at developing a species-specific, orally-delivered contraceptive vaccine that can be easily spread out in the wild for eastern gray kangaroos. Current research reveals the vaccine can provide sterility for at least three years. Ongoing drug trials will take researchers approximately 10 years to establish the long-term effectiveness of the drug and its environmental and ecological safety. Until this time, the cull will be the only safe and economic solution to the kangaroo population problem.

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National Science Education Standards

Grades 5-8:

Content Standard C: Life Science

Fundamental concepts and principles that underlie this standard include:

  • Regulation and Behavior
    • All organisms must be able to obtain and use resources, grow, reproduce, and maintain stable internal conditions while living in a constantly changing external environment.
  • Populations and Ecosystems
    • A population consists of all individuals of a species that occur together at a given place and time. All populations living together and the physical factors with which they interact compose an ecosystem.
    • The number of organisms an ecosystem can support depends on the resources available and abiotic factors, such as quantity of light and water, range of temperatures, and soil composition. Given adequate biotic and abiotic resources and no disease or predators, populations (including humans) increase at rapid rates. Lack of resources and other factors, such as predation and climate, limit the growth of populations in specific niches in the ecosystem.
  • Diversity And Adaptations of Organisms
    • Extinction of a species occurs when the environment changes and the adaptive characteristics of a species are insufficient to allow its survival. Fossils indicate that many organisms that lived long ago are extinct. Extinction of species is common; most of the species that have lived on the earth no longer exist.

Grades 9-12:

Content Standard C: Life Science

Fundamental concepts and principles that underlie this standard include:

  • The Interdependence of Organisms
    • Organisms both cooperate and compete in ecosystems. The interrelationships and interdependencies of these organisms may generate ecosystems that are stable for hundreds or thousands of years.
    • Living organisms have the capacity to produce populations of infinite size, but environments and resources are finite. This fundamental tension has profound effects on the interactions between organisms.
  • Matter, Energy, and Organization in Living Systems
    • The distribution and abundance of organisms and populations in ecosystems are limited by the availability of matter and energy and the ability of the ecosystem to recycle materials.

Content Standard E: Science and Technology

Fundamental concepts and principles that underlie this standard include:

  • Understandings About Science and Technology
    • Scientists in different disciplines ask different questions, use different methods of investigation, and accept different types of evidence to support their explanations. Many scientific investigations require the contributions of individuals from different disciplines, including engineering. New disciplines of science, such as geophysics and biochemistry often emerge at the interface of two older disciplines.

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