Male humpback whales in New Caledonia have learnt the complex songs of east Australia's population with remarkable accuracy, a new study has discovered.
Between 2009 and 2015, researchers, mainly from the University of Queensland, collected acoustic recordings from Peregian Beach on the coast of southeast Queensland and the southern lagoon of New Caledonia.
By looking at song patterns the researchers discovered songs from east Australia's humpback whale population had been transmitted to the New Caledonian whales.
In other words, they learned their songs.
The study detailed how a total of 353 complete 'song cycles' - 10 to 36 per year, per population - were taken from 89 recordings. Each year, such song cycles were transcribed from a minimum of six whales.
The findings have recently been published in the journal, Scientific Reports.
The study said humpback whale song is a long and complex vocal display produced only by males.
Researchers analysed six separate 'song types' (slightly different song arrangements), four 'revolutions' (replacements of existing songs) and two 'evolutions' (small, progressive changes to songs) first recorded in the east Australian population and transmitted to the New Caledonian population the following year.
They found the whales in New Caledonia had learned each song with high accuracy, regardless of the pattern's complexity.
"Each year we observed them they sang a different song, so it means humpback whales can learn an entire song pattern from another population very quickly, even if it's complex or difficult," researcher Jenny Allen said.
To determine song complexity, the researchers measured both the number of sounds the whales made and the length of the sound patterns.
Allen said the whales have to be physically close to exchange songs, roughly within 2km of each other.
The researchers said they don't know where the whales are meeting, but the Antarctic feeding grounds or the New Zealand migration corridor, shared by both populations, were named as locations for such "close acoustic contact".
The researchers also said the movement of entire song patterns across multiple populations has not been documented in any other location worldwide or any other species except humans.
"This really indicates a level of 'cultural transmission' beyond any observed non-human species."