WOMBAT LIFE CYCLE
According to Mallett & Cooke (1986), the Northern Hairy-nosed Wombat is a seasonal breeder. However, the timing of reproduction has shown to correlate directly with both altitude and latitude, that is, the young is weaning when there is a maximum potential growth period of temperate grasses; this is usually during Spring or early Summer (Mallett & Cooke 1986).
The gestation period is relatively short, approximately 20-22 days. Usually only one offspring is conceived at a time, however, twins are known to occur. At birth, the joey is extremely underdeveloped and hairless, weighing in at approximately 2 grams. Immediately after birth, the joey will crawl into the pouch of its mother, that is backward facing to avoid dirt entering it when digging; there it will attach to one of two teats which will then swell up inside the mouth of the joey to prevent it from detaching. The young will leave the pouch at approximately 8 months of age, however, won't vacate it permanently until 9 months. At 12 months of age, the young will be fully weaned and this is the duration in which they grow very rapidly, that is, their body weight may double within the first 3-8 months of weaning (Wells 1973). The Northern Hairy-nosed Wombat will typically reach adult size at 2 years of age in the wild, however, under captive conditions, adult size and reproductive maturity may not be reached until 3 years (Wells 1973). The average lifespan of a Northern Hairy-nosed Wombat is more than 20 years.
The gestation period is relatively short, approximately 20-22 days. Usually only one offspring is conceived at a time, however, twins are known to occur. At birth, the joey is extremely underdeveloped and hairless, weighing in at approximately 2 grams. Immediately after birth, the joey will crawl into the pouch of its mother, that is backward facing to avoid dirt entering it when digging; there it will attach to one of two teats which will then swell up inside the mouth of the joey to prevent it from detaching. The young will leave the pouch at approximately 8 months of age, however, won't vacate it permanently until 9 months. At 12 months of age, the young will be fully weaned and this is the duration in which they grow very rapidly, that is, their body weight may double within the first 3-8 months of weaning (Wells 1973). The Northern Hairy-nosed Wombat will typically reach adult size at 2 years of age in the wild, however, under captive conditions, adult size and reproductive maturity may not be reached until 3 years (Wells 1973). The average lifespan of a Northern Hairy-nosed Wombat is more than 20 years.
Pictured to the right is a newly born wombat joey attached to its mother's teat (Mammalogy n.d.).
The image to the left shows a well-developed Southern Hairy-nosed Wombat joey inside the mother's pouch (San Diego Zoo Global 2013).
The image to the right shows a Southern Hairy-nosed Wombat mother and her joey at approximately 9 months of age and permanently out of the pouch (Zoos Victoria 2012).
References:
Mallett, K.J. & Cooke, B.D. 1986, ‘The Ecology of the Common Wombat in South Australia’, Nature Conservation Society of South Australia, Adelaide, pg 55
Mammalogy n.d., 'Noneutherian Mammals: Monotremes and Marsupials', viewed 13 October 2013,
http://www.life.umd.edu/classroom/bsci338m/Lectures/Monotremes.html
San Diego Zoo Global 2013, 'Wombats', viewed 13 October 2013,
http://library.sandiegozoo.org/factsheets/wombat/wombat.html#repro
Wells, R.T. 1973, 'Physiological and Behavioural Adaptations of the Hairy-nosed Wombat', Unpublished PhD Thesis, University of Adelaide, Adelaide.
Zoos Victoria 2012, 'Wombat Birth', viewed 13 October 2013,
http://www.zoo.org.au/news/wombat-birth
Mallett, K.J. & Cooke, B.D. 1986, ‘The Ecology of the Common Wombat in South Australia’, Nature Conservation Society of South Australia, Adelaide, pg 55
Mammalogy n.d., 'Noneutherian Mammals: Monotremes and Marsupials', viewed 13 October 2013,
http://www.life.umd.edu/classroom/bsci338m/Lectures/Monotremes.html
San Diego Zoo Global 2013, 'Wombats', viewed 13 October 2013,
http://library.sandiegozoo.org/factsheets/wombat/wombat.html#repro
Wells, R.T. 1973, 'Physiological and Behavioural Adaptations of the Hairy-nosed Wombat', Unpublished PhD Thesis, University of Adelaide, Adelaide.
Zoos Victoria 2012, 'Wombat Birth', viewed 13 October 2013,
http://www.zoo.org.au/news/wombat-birth