Scientists are taking advantage of the quiet during the COVID-19 pandemic to learn the language of a rare species of dolphin.
By ABC Health
The Burrunan dolphin lives in the Gippsland Lakes and Port Phillip Bay in Victoria.
Because of COVID-19, there have been fewer boats on the Gippsland Lakes, and subsequently, much less noise.
Scientists have set up acoustic sound monitoring in the Gippsland Lakes and for the first time, are listening to what the Burrunan dolphin has to say.
Kate Robb, from the Marine Mammal Foundation, said she had already learned a lot from listening.
“Dolphins have a repertoire; Each of these sounds can correlate to a behaviour and this is known as their acoustic repertoire,” Dr Robb said.
“Out on the boat we do a focal follow, in which we record the surface visual behaviour of the dolphins while underwater audio recordings are taking place.
“Once we put it all together we match sounds and behaviours and look for correlations.”
She said they had already translated some of the sounds the dolphins make.
“Dolphins do a buzzing sound. This is called an echolocation. They do this to find their food. So we already know this sound correlates to feeding,” Dr Robb said.
Dr Robb and her team could recognise each dolphin individually just by looking at them.
It turns out each dolphin also has its own name.
This is called a ‘signature whistle’.
“We’re learning about the Burrunun dolphin’s signature whistle during this time, so like my name is Kate, they have a way of saying their own name,” Dr Robb said.
“The idea behind a signature whistle is that it’s a form of greeting — we don’t want to anthropomorphise though.
“Eventually if we see a particular behaviour we can expect that kind of sound [the signature whistle], which is a sort of language in itself, but isn’t exactly a ‘hey, how are you doing?’.
“We’re trying to identify the signature whistle of each of the dolphins in the Gippsland Lakes pod.”
The complex social life of a dolphin
Dr Robb said she expected to learn language around behaviours, including feeding and mating.
The dolphins have a complex social life.
Two of the Burrunan dolphins, Yoda and Trunci have been best friends for over a decade.
“Yoda and Trunci are our resident males, they’ve been seen together since 2006,” Dr Robb said.
“They have a very strong bond and what we would call an alliance.
“These boys are always seen together.”
Dr Robb is expecting to learn the language around mothers and calving.
“The females tend to hang out in nursery pods, with other mums with the same age calves,” she said.
“We have matriarch females who are no longer calving but hang out like grandmother dolphins within these pods.
“The mums share care their calves so they can take time to feed.”
Insight into night activity
The acoustic monitoring is also helping Dr Robb and her team learn about the movement of the Burrunan dolphins during the night for the first time.
“This will tell us for the first time ever what night time activity is for dolphins,” she said.
“It seems the dolphins are using the area equally during the night as the day.
“They don’t sleep, they shut down half their brain and rest instead. We call this milling — they can do this at any time of day or night.”
Dr Robb said she expected the dolphins could be talking more during this quieter time on the Gippsland Lakes as the measures aimed at protecting the dolphins during busy boating periods are not always practised.
“There are regulations to protect the dolphins, that boats aren’t allowed within 100 metres, locals respect this, but during peak periods, we see a high number of breaches.”
Dr Robb said there might never be another opportunity like this quiet time on the Gippsland Lakes.
“It’s a controlled experiment we’ll never get to do again,” she said.
Originally published at News