Scientists from Syracuse University in New York hope the unique vocal characteristics found in North Atlantic right whales could help in conservation efforts of the endangered species.
When you pick up the phone, it’s easy to tell the difference between your dad’s and mom’s voice. The source-filter hypothesis, which was proposed for human speech, suggests that sound sources combine independently to make distinct vocals. Researchers applied the same theory to the endangered North Atlantic right whales and studied a combination of vocal features—such as the length of their calls and the fundamental and harmonic frequencies. The study, which will be presented at the 169th meeting of the Acoustical Society of America, found that 13 different whales could be pinpointed from the individual calls they made.
North Atlantic right whales make a range of different calls, such as the 'gunshot' sound made by a lone adult male and the 'scream' call produced by females. Researchers specifically analyzed the ‘upcall’ of the North Atlantic right whale, which is a type of call largely used to let other whales know of their presence and to check in with them. The upcall is produced by both males and females, and can be produced by a range of age groups. Researchers Jessica McCordic and professor Susan Parks studied over a decade of archived acoustic data, which were gathered from suction cup sensors attached to North Atlantic right whales.
McCordic says she didn't find much of a variation in the harmonic frequencies of the upcalls, but instead "one of the variables that came out as most important in discriminating the individuals was the duration of the call.”
"The analysis classified the whales well above chance levels, so that was really exciting," she adds.
Researchers hope to use the same approach to identify North Atlantic right whales in the wild, which could help with conservation efforts. The North Atlantic right whales are one of the most endangered of all large whales, according to the World Wildlife Fund. Researchers estimate the current population, which has remained critically endangered since protective measures were put in place in the 1930s, to be around 450 whales. The North Atlantic right whale is particularly vulnerable to ship collisions and getting entangled in fishing equipment.