San Francisco State Professor Roger Bland recorded 4,378 blue whale songs near Half Moon Bay, California using underwater microphones. He then analysed their B calls or the second half of their long songs. His analysis showed all the B calls made by the whales were the same frequency of 16.02 Hertz, four octaves below middle C.
Bland said, “If whales are so super accurate in always calling at the exact same pitch, then it’s possible that they could be able to detect tiny shifts in other whales’ calls caused by the Doppler shift.” (Source: San Francisco State News)
The difference in pitches for the thousands of whale calls was only one half of one percent, which means the whales have “perfect pitch”. Normally this is a term applied to humans who can distinguish between tones and semi-tones to the degree they can hear and identify them all.
For blue whales it is thought their perfect pitch is something that could help them find mates. It is mainly males who produce the songs. Females could use their very sensitive sound detection to determine if the call is from a male whale moving toward or away from because sound pitch varies according to the speed of emitter. Known as the Doppler Shift, it is the effect of a pitch being higher when a sound is traveling toward a listener and lower when moving away.
Blue whale calls are two parts – an A call that is a series of pulses, and a B call which is a long sustained tone, sometimes called a moan. Professor Bland noted their pitch sensitivity allows them to stay connected through sound, “…like a choir singing together where they all mutually tune in to the same frequency.” (Source: MercuryNews.com) Here is a sound clip from his research.
Bottlenose and Guyana are two separate dolphin species. Each species has its own calls and sounds. An American researcher studied the two dolphin species interacting off the coast of Costa Rica. Laura May-Collado from the University of Puerto Rico found when the two separate dolphin species interacted they used a third communication style, created for those shared moments. She was near Costa Rica’s Gandoca-Manzanillo Wildlife Refuge off the coast when she made the discovery.
Bottlenose dolphins use longer, lower frequency sounds when they are together. Guyana dolphins use higher frequency sounds with a particular structure. May-Collado observed when the two species swam together they used sounds that were different from their normal style. They actually used sort of a hybrid or compromised style which means they both changed their communication to be more like each others. The bottlenose dolphins used somewhat higher sounds and shortened them, and the Guyana dolphins used slightly lower sounds, that were more like the ones made by the Bottlenose dolphins.
She said, “I was surprised by these findings, as I was expecting both species to emphasize, perhaps exaggerate, their species-specific signals. Instead the signals recorded during these encounters became more homogenous.” (Source: UPI)
Bottlenose dolphins are larger than the Guyana species, and the inter-species interaction can be antagonistic with the Guyana dolphins harassing the larger ones. So far her research has not determined if one species is mimicking another, or if their communication style is actually changing.
She speculated the smaller Guyana dolphins could be using the language of the Bottlenose dolphins to show they are friendly with the larger ones that harass them.
Another researcher says dolphins don’t only use sounds for communication with each other, “there is strong evidence that dolphins are able to ‘see’ with sound, much like humans use ultrasound to see an unborn child in the mother’s womb. The CymaScope provides our first glimpse into what the dolphins might be ‘seeing’ with their sounds.” (Source: Speakdolphin.com)
