BBC broadcasts the remarkable, newly discovered courtship holler of the koala:
Dr [William] Ellis and his colleagues [from the University of Queensland], who report their findings in the journal Behavioural Ecology, caught and fitted satellite tracking collars to 12 koalas – six males and six females.
“We have these solar-powered mobile phones that record sound for a few minutes every half hour and upload it to a server here in Brisbane – so I can hear how much bellowing is going on,” he explained.
The researcher says the males “advertise themselves” by bellowing.
“We see these big spikes in female movement when there is more bellowing going on, so it really seems that the females are going and searching out the males.”
“Whatever they’re doing vocally, it seems really quite complex,” said Dr Ellis.
Audio at the link.