A scientist tracking koalas films unexpected social behavior between young males

It's a cold, drizzly night in a forest west of Melbourne. I'm sitting on a damp log, clutching a thermos of lukewarm tea and watching a koala snooze on a branch above me. Suddenly, it lifts its head. I sit up straight, pen poised to record what happens. But the koala simply yawns and resumes the blob position. I sigh and take another sip of tea.