Mother whales WHISPER to evade orcas while swimming with their calves

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These marine mammals, which can grow to be upwards of 45 feet long and reach 20 feet even as calves, are known to prefer cloudy waters that will keep them hidden. And, scientists now say they may even lower their voices to stay off orcas’ radar


Mother whales WHISPER to evade orcas while swimming with their calves

  • Study tagged whales with sound recorders in Flinders Bay, off Western Australia 
  • They found that the whales appear to stay in the noisy surf, and keep voices low
  • This likely helps them stay undetected by orcas, which are known predators 

They might be twice the size of the top ocean predators, but southern right whales don’t take any chances when it comes to protecting their babies.

These marine mammals, which can grow to be upwards of 45 feet long and reach 20 feet even as calves, are known to prefer cloudy waters that will keep them hidden.

And, scientists now say they may even lower their voices to stay off orcas’ radar.

In a new study, researchers have recorded what they say are essentially whale whispers, as the animals hide out in the noisy surf and keep communications to a low to stay unnoticed. 

These marine mammals, which can grow to be upwards of 45 feet long and reach 20 feet even as calves, are known to prefer cloudy waters that will keep them hidden. And, scientists now say they may even lower their voices to stay off orcas’ radar

Researchers studied the conversations between southern right whale mothers and their calves in Flinders Bay, of the southern tip of Western Australia.

Previous research has shown that humpback whales whisper to protect their young, too, the team notes.

But, eavesdropping on whales isn’t easy.

‘One of the initial challenges was getting to know the whales in our study area,’ said Mia Nielsen from Aarhus University, Denmark.

‘The number of whales that frequent the bay is low.’

The team tagged resting whales with sound recording devices while they were perched near the surface.

According to the researchers, the mother whales and their calves often stick close together and seek shelter in the surf, where they’re better concealed.

Using the tags, the experts were able to determine that they also appear to whisper to each other, lowering the sound of their calls occasionally during a dive.

‘The tags stayed on the mothers for about 7 hours on average,’ Nielsen said, though the calves shook theirs off in about 40 minutes.

‘Southern right whales are very physical with each other, the calves spend a lot of time rubbing against the mother and rolling over her back, tail, and rostrum.’

They might be twice the size of the top ocean predators, but southern right whales don’t take any chances when it comes to protecting their babies. File photo

They might be twice the size of the top ocean predators, but southern right whales don’t take any chances when it comes to protecting their babies. File photo

The team then analyzed the recordings – which again posed a few challenges.

‘It was difficult to assign the calls to either the calf or the mom, because they are so close to each other,’ Nielsen said.

There were, however, two distinct types of calls: grunting and ‘mooing.’

And, they found that the volume was surprisingly quiet, often getting drowned out by the waves within a few hundred meters.

The researchers say this likely makes it difficult for killer whales to pick up on their calls.

WHAT DO WE KNOW ABOUT WHALE SONG?

For a long time it was believed that whales sang solely for mating purposes.

But some experts suggest the songs also help the mammals explore their surroundings.

Researchers have recorded humpback whales changing their calls when they move to new pastures in order to match the songs of others around them.

Learning these songs may help whales pinpoint one another and group together better when in unfamiliar waters.

Researchers have recorded humpback whales changing their calls when they move to new pastures in order to match the songs of others around them (file photo)

Researchers have recorded humpback whales changing their calls when they move to new pastures in order to match the songs of others around them (file photo)

It is tricky for scientists to study how whales sing, as the shy beasts are notoriously difficult to observe, and each species vocalises differently.

Humpback whales sing using folds in the vocal box that vibrate at low frequencies as air is pushed over them.

It has been suggested they have special air sacs adjoining these vocal chords which connect to the lungs.

These allow the whales to pass air between their lungs, the sacs, and the vocal chords without losing any of their precious air supply.

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