Everything you always wanted to know about kangaroo reproduction, but were afraid to ask.
by Carl-Johan SVEDBERG SANTINI
Discover how kangaroos can have no less than three babies at the same time, and why it matters both environmentally and economically.
Everybody knows kangaroo mothers protect and carry their babies in a front-opening pouch surrounding four teats. What some people still don't know is that although a doe (a female kangaroo) produces a single young per litter, she can, more often than not, look after three offspring at the same time! Not only does the doe carry a youngster in her pouch, but she also often keeps a joey there too. A joey is a newly born young who is in an immature state after gestation and needs to stay in the pouch for another six months. When the oldest baby is getting too big, he can't be carried any longer but stays with his mother. Finally, the doe can have an embryo in the womb. Amazingly, she is able to stop the development of a fertilized egg until the joey vacates the pouch. Most kangaroos are able to breed all year round.
Having three babies at the same time, means this population of prolific breeders is increasing dramatically quickly, particularly now that one of its main predators, the Tasmanian tiger, has been extinct for decades. According to government studies, "a kangaroo population can increase fourfold in five years if it has continuous access to plentiful supplies of food and water."* The Kangaroo Industry Association of Australia (KIAA) claims that kangaroos increased from 30 million in 1998 to about 58,6 million in 2002. This surge has had drastic repercussions on the ecosystem: kangaroos are avid herbivores in a country where vegetation is limited.
This is music to the ears of industrialists who use kangaroos for meat, skins and furs. Four out of the 60 different species of kangaroos are "commercially harvested" in the wild by licensed hunters, under the provisions of the Federal Environment Protection and Biodiversity Conservation Act 1999. In 2004, the kangaroo industry brought about $200 million according to the Australian Wildlife Protection Council (AWPC). It exports meat to more than 55 countries. Kangaroo skin is renowned for being strong and light, which makes it ideal for sporting footwear.
Not all Australians are happy with this organised culling of their national symbol. Activist groups like AWPC or Vegetarians International Voice for Animals (VIVA) fight for the macropod (i.e. big-footed) mammal which adorns Australian postage stamps and coinage to be left alone. They stress their contribution to the tourist trade and the fact that some species are endangered.
But kangaroo demographics are no joke.
Sources: *www.dfat.gov.au/facts/kangaroos.html; www.christiananswer.net/q-aig/aig-kangaroo.html; www.encarta.man.com; www.kangaroocenter.com; www.biology.iastate.edu ; www.Rogerwilliamsparkzoo.org; www.kangaroo-industry.asn.au; www.awpc.org.au; www.viva.org.uk