Humpback whales’ migration along Australia’s east coast best time to hear marine animals sing
Just beneath the water’s surface off Queensland’s coast, humpback whales can be heard singing clearly to each other, as new research shows they are learning complex tunes from other regions.
About 40,000 humpback whales are on their annual migration along Australia’s eastern coastline and, according to Lady Elliot Island reef guide Jacinta Shackleton, it is as easy as putting your head under water to hear them.
“You can actually hear their song right at the surface of the water, and as you get deeper, they get louder,” she said.
“The closer they are to you, the louder the song … it’s so incredible.”
Their songs change every year, and researchers at the University of Queensland, including study leader Jenny Allen, have found neighbouring whale populations are learning each other’s distinct tunes.
“The whales in east Australia sing a particular song pattern … and then the next year, whatever song east Australia was singing, the New Caledonia whales will be singing,” Dr Allen said.
“So, the song is learned from one population to another.”
Transmitting culture through song
The study examined songs of male humpback whales from eastern Australia and New Caledonia between 2009 and 2015 to decipher how culture transmits between the populations.
Dr Allen said it showed the whales learnt quickly and with remarkable accuracy.
“What we found was that they don’t have to make it dumbed down at all,” she said.
“They can keep it as complicated as it was originally, and they’re able to learn the whole thing.”
It is still unknown how close the populations must be to learn songs from one another.
“There’s a couple of hypotheses that they might be mixing on the migration route,” Dr Allen said.
“Both populations have a shared migration route that goes past New Zealand on their way to Antarctica, which is their feeding ground.”
Dr Allen said there were some places where the singing was easy to hear.
“When they get to their breeding grounds, which are around the Whitsundays area, that’s where they’ll be singing the most,” she said.
Hervey Bay is also an important stop for mothers and calves on their return travels south.
“If you stick your head in the water at Hervey Bay, you have a good chance of hearing singing,” Dr Allen said.
Whale-watching season begins
The peak whale watching season is from July to October.
Ms Shackleton said that was the best time to see and hear the giants of the deep.
“It’s pretty incredible for scuba divers because it does get really loud when you’re down there,” she said.
“I love listening to the variations in their songs. You get everything from high-pitched squeaks to deep grunts.”
Understanding why whales sing
Researchers still do not know why whales sing, but they believe it could be linked to mating and reproduction.
“Females will make sounds, but they don’t sing … it’s only the males that sing,” Dr Allen said.
“What we don’t know is sort of who it’s aimed at.
“We don’t know if the males are trying to impress the ladies, or if they’re trying to intimidate the other males, or both.”
Dr Allen said the research helped understand how these whale populations interacted and how to better protect them.
“The east Australia population is doing really well, but the New Caledonia population is still endangered,” she said.
“So, getting an understanding of how these populations interact is going to help us more effectively protect them and more effectively manage how humans interact with them.”