Whale-watching is a well-known pursuit in Australia for locals and visitors, thanks to our extensive coastline and large number of whales that can be seen off our coast.
These range from humpback whales, which are the most common species seen, to southern right whales, minke whales and blue whales.
Now a team of researchers at the Friedrich–Alexander University in Germany has released details of a ground-breaking new study that they believe will soon determine how killer whales communicate.
To understand this communication process between whales, they used deep learning to analyse a large number of audio recordings of the whales communicating and then compared these with the animals’ behaviour at the same time.
“The language of killer whales is particularly well-suited to analysis. They often communicate within the group, for example while hunting or with juveniles. They also interact with other killer whale pods. The language used by the various groups even varies slightly, similarly to our [human] dialects,” explained Professor Elmar Nöth, Chair of Computer Science 5 (Pattern Recognition) at the university.
First of all, the team isolated the clicks, whistles or pulsed calls typical of killer whales, by using deep learning and filtering out other sounds originating from, for example, ships or seals.
“We are now able to reliably identify the killer whale segments,’ said Nöth. “At the moment, the researchers are working to split the recordings automatically into sequences. These recurring sequences consist of several sounds. If the sequences show similarities and occur repeatedly in the same situations, we can presume that it is the same message.”
According to Nöth, the team once observed the interaction between two killer whale pods.
The juveniles moved away from the rest of the pod. “The calls we recorded may mean something like ‘Where are you?’ – “We’re over here”– “Come on, it’s time to go”’, explained Nöth.
But how can the researchers check their hypotheses?
“When analysing human language, you can usually enlist the help of someone who is bilingual. That is not the case with animals,” said Nöth.
Big volume of material to study
The team of researchers must therefore compare the sounds with the whales’ behaviour. The aim is to draw up a glossary of killer whale vocabulary. They are collaborating closely with biologists, continually discussing and comparing their findings.
The researchers say they have almost 20,000 hours of material available for them to study.
Moving into the next phase of the project, the researchers hope to make the software they use to analyse the killer whale sounds available to the public. As Nöth explains: “Our algorithm can also be used to study other animals and their languages.”