They don't hang around. The resident males did fare well, however, siring about one or two offspring during each breeding season from September through March. But they're obviously not able to father all of the offspring. Scientists are unsure whether the males from the outside come from other colonies or lead a life of philandering. The test results make scientists feel better about the fears of mating between close relatives, but according to Sharkey, the introduction of new blood into colonies demands bushland corridors for the nomad males to travel through.
Koalas sometimes have conflicting sexual strategies.
He says this increases their chance of giving birth to healthy offspring to carry their genes through the generations. Females squawk when they are mounted, which is thought to be evolved behavior intended to attract the attention of the biggest, strongest resident males. To put a human take on it, it is thought that a resident male hears her and runs to her rescue. A female who only mates with one partner could end up with offspring carrying harmful genes. Koalas are disappearing slowly in Queensland, particularly in the southeast part of the state, according to Environment Australia.