PLETTENBERG BAY NEWS - Can dolphins talk? How do they say "hello"?
While sounding a bit far-fetched, dolphins do communicate in their own "language".
And the highly endangered humpback dolphin has its own chatter.
Those found in the bay of Plett appear more chatty than the ones recorded at Robberg Nature Reserve.
Or this is how bioaccoustics specialist Sasha Dines explains the recording of the natural sounds of humpback dolphins she is studying, using underwater equipment called a hydrophone.
Whistle
Humpback dolphins - Dines' study species - whistle.
They are restricted to small coastal populations averaging between two and five dolphins per pod.
They like shallow waters and that is why they're so difficult to study - recently Dines and her colleagues published a paper that recorded broken and damaged rostrums (beaks) of these animals, possibly caused by them foraging and feeding close to the rocky shore and in reefs.
"They don't go too deep," says Dines.
"A lot of them have broken rostrums" - probably from ramming into the reefs.
"There are likely fewer than 500 left in South Africa and they are the most endangered resident marine mammal species in our waters," Dines told the Plett Ocean Festival and Marine Science Symposium on Saturday 22 June.
But, she says, there is still a lack of scientific knowledge about the threats they face.
Dines says they communicate with three types of sounds: whistles, clicks and burst pulses, with Dines focusing her research on one type of whistle - a signature whistle. These are learned, individually distinctive whistles which can be stable for nearly 50 years.
Dolphin's 'name'
They are often compared to a dolphin's "name" as they are used to broadcast the identity of the individual to others in the group.
"We have identified the first long-term use of a likely signature whistle in a humpback dolphin using 11 years of acoustic and video recordings of this individual," says Dines.
So far Dines has catalogued around 40 humpback dolphin signature whistle types from along the South and East coasts of South Africa.
"Hi" this is my name, a humpback dolphin could be whistling.
"When they are making these contact calls and calling out to each other, much of the time it's linked to social behaviour," says Dines.
"Socialising with one another: often it's while playing or mating. Socialising can encompass so many things.
"They might be playing with each other, bonding, or they can be involved in a whole suite of things using these calls for socialising.
"That's opposed to something like when they're travelling, where they won't be using their signature whistles to communicate.
Echolocation
"They won't need to communicate their identity as they travel. They're all heading in one group in one direction - they're all travelling one common path and so they will likely be using echolocation more.
"Also, when they're resting in areas, sleeping maybe, there won't be many calls either."
So definitely they're more 'talkative' in a bay during certain behaviours or compositions of the group, when they are close to the hydrophones at certain times of the day.
Dines deployed two recording devices, hydrophones, in Plettenberg Bay, one placed near the Beacon Island Hotel and the other at Robberg .
The humpback dolphins recorded at Beacon Island were more chatty than the ones at Robberg.
"One of the reasons for less chatting, and I hypothesise here, is that they might be travelling more when at Robberg, or because of potential predator threats such as shark activity and they don't want to be too vocal. There could be several reasons for it," says Dines.
The recording equipment is moored and left for a month or two at a time.
"We're not there to see what the animals are doing and don't have photographs or visuals to see what they are up to.
"That's one of the big puzzle pieces that we're missing, we can't see what they are up to," she adds.
Dines is linked to Seasearch Research and Conservation, and is at present completing her doctorate through the University of Stellenbosch.
Can dolphins talk? How do they say "hello"?
While sounding a bit far-fetched, dolphins do communicate in their own "language".
And the highly endangered humpback dolphin has its own chatter.
Those found in the bay of Plett appear more chatty than the ones recorded at Robberg.
Or this is how bioaccoustics specialist Sahsha Dines explains the recording of the natural sound of humpback dolphins she is studying, using underwater techniques like hydrophones.
Humpback dolphins – Dines' specialist area – whistle their own names.
They are restricted to small coastal populations averaging between two to five dolphins per pod.
They like shallow waters and that is why they're so difficult to study – recently there was a science paper that recorded the broken and scarred noses of these creatures, caused by them foraging and feeding close to rocky shore lines.
"They don't go too deep," says Dines.
"A lot of them have broken or bashed noses, probably from ramming into the reefs.
"Nearly 250 individuals have been identified and they are the most endangered cetacean species in our waters," Dines told the Plett Ocean Festival and Marine Science Symposium on Saturday 22 June.
But, she says, there is still a scientific lack of knowledge about the threats they face.
Dines says they communicate with three types of sounds: whistle, eco location clicks and a signature whistle- they are individually distinctive and igo about whistling there "name" "It's the first time the signature whistle has been identified in a humpback ," says Dines.
So far 35 humpback dolphins have been identified by their signature whistle.
"Hi" this is my name, a humpback dolphin could be whistling.
"When they are making those noises and calling out to each much of the time it's linked to social beahviour," says Dines.
"Socialising with one and another: often it's while foraging for food. Or mating. Socialising can encompass so many things.
They might be playing with each other, bonding, or they can be involved in a whole suite of things using these calls for socialising.
"That's opposed to something like when they're travelling, they won't be calling as much .
"They won't need to communicate. They're all heading in one direction – they're all travelling one common path and the need to communicate is less so.
"Also, when they're resting or de-stressing in areas, sleeping maybe, there won't be many calls either."
So definitely they're more 'talkative' in a bay during day time when they're foraging in this area, because that's where all the fish are …
"At night they're resting in this area because it's shallower…"
Dines has two hydrophone recording devices, one placed near the Beacon Island Hotel and the other at Robberg .
The humpback dolphins recorded at Beacon Island were more chatty than the ones at Robberg.
"One of reasons for less chatting, and I hypothisise here, is that they might be travelling more.
"Or because of shark activity there and they don't want to be too vocal. There could be several reasions for it," says Dines.
The recording equipment is moored and left for a month or two at a time
"We're not there to see what the animals are doing and don't have photographs or visuals as to what they are up to.
"That's one of the big puzzle pieces that we're missing, we can't see what they are up to," she adds..
Dines is linked to SeaSearch, and is at present completing her doctorate through the University of Stellenbosch.
‘We bring you the latest Garden Route, Hessequa, Karoo news’
