AN AUSTRALIAN skink is the first reptile known to live in a stable nuclear family, where two parents live alongside their juvenile offspring.
Some mammal and bird species, and even a few fish species, are found in similar family units. But the discovery that a reptile also lives this way suggests that the nuclear family could be the ideal arrangement for a whole range of animals.
Dave O鈥機onnor and Rick Shine from Sydney University studied more than 200 black rock skinks at a site in the Blue Mountains of New South Wales. Some 83 per cent of all the social groups containing more than one adult included a mating pair, a DNA analysis of the tips of the skinks鈥� tails revealed. What鈥檚 more, 65 per cent of juveniles lived in family groups with at least one of their parents (Molecular Ecology, vol 12, p 743). Of these juveniles, two-thirds lived with both parents, some for the whole of the three-year-study.
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Why they choose nuclear families is not obvious, as reptile parents do not care for their offspring. 鈥淲e suspect it is linked to protection from being eaten,鈥� says O鈥機onnor. 鈥淏lack rock skinks are aggressive to unrelated juveniles 鈥� they鈥檙e just another food item.鈥� Herpetologist Allen Greer at the Australian Museum in Sydney agrees, adding that lizards have a life-expectancy of between 10 and 15 years. They may need to hang out with their parents to stand a good chance of making it to adulthood.