For example, scientists think the facial tumor disease is spread by devils biting each other while mating.
If the species can hang on long enough, devils that bite less or that are better able to avoid bites will have more chances to reproduce, Jones said.
Eventually these milder-tempered devils could form the bulk of their populations because they are less likely to pass on the disease.
"Teen Sex" to Stay?
Since early breeding allows female devils to give birth at least once before falling victim to the disease, it could become an "evolutionarily fixed" trait for the species, scientists say.
"Most animals are dying at about two-and-a-half years old, so they may die halfway through raising their young," Jones said. "Any animal that breeds as a one-year-old is going to have a better chance of passing on its genes."
This trait makes sense, said Esben Moland Olsen, a biologist at the University of Oslo in Norway who was not involved in the study.
Olsen has documented a similar shift toward younger breeding in populations of cod threatened by overfishing. His studies suggest early reproduction is already becoming a fixed part of the fish's life cycle.
"Based on the latest data I have seen, the change seems to be holding," Olsen said.
"Although cod populations have not fully recovered, I tend to think that things would have looked even worse in the absence of a life-history change towards early maturation."
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