for National Geographic News
The famously feisty mammals found on the Australian island of Tasmania typically live for five to six years and don't begin mating until age two. But in some populations threatened by the contagious and disfiguring facial tumor disease (see video), more than half of females one year old or younger have begun breeding.
"This represents a sixteen-fold increase in precocious sex for the species," said study leader Menna Jones of the University of Tasmania in Australia.
The team believes some females are reaching sexual maturity faster and reproducing sooner because the hefty toll of the disease has freed up food and created less competition for mates.
The finding is detailed in this week's issue of the journal for the Proceedings of the National Academy of Sciences.
Early breeding could help explain how some devil populations have survived despite being ravaged by the rare facial cancer for more than a decade, said study co-author Clare Hawkins, also of the University of Tasmania.
Yet "despite these compensations, the numbers in all diseased areas are continuing to steadily decrease," Hawkins added. "The compensation doesn't appear—at least so far—to be sufficient."
Scientists fear that, if trends continue, wild Tasmanian devils could disappear as soon as 2030. (See story.)
While early breeding alone may not be enough to prevent extinction, it could buy the animals enough time to adapt to the disease.
"Because the disease is consistently fatal, devils are under very, very strong selection on a number of fronts," Jones said.
The natural selection could be for "disease resistance, early breeding, or behaviors that keep the devils out of trouble," Jones said.
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