
Every year, thousands of humpback whales journey up Australia's coast to sub-tropical waters for calving.
But researchers say an increasing number appear to be giving birth in colder southern waters in what could expose youngsters to more risks.

Every year, thousands of humpback whales journey up Australia's coast to sub-tropical waters for calving.
But researchers say an increasing number appear to be giving birth in colder southern waters in what could expose youngsters to more risks.