Blue whales have conversations 600 miles apart

Blue whale

Scientists have discovered that male blue whales (it is only the males who produce whale song – src: The Times) have conversations with other whales which are 600 miles away. They also discovered that before they migrate south to warmer waters they appear to be vocalising their intentions while they gorge on krill to build up reserves for the journey. They travel 4,000 miles when they migrate. The scientists hope that knowing this they can predict the movement of blue whales and thereby avoid collisions with shipping.

Blue whale

Photo: NOAA – copyright free.

Blue whales mainly sing during the night but as they prepare to travel south for the winter their trills and bellows mainly occur during the daytime. The researchers discovered this by monitoring their movements and their vocalisations to find a link between the two. The research was carried out over a five year period.

Blue whales are the loudest animals on the planet. As mentioned in the title, their calls can travel for more than 600 miles underwater and it is now believed that these sounds can be picked up by other whales hundreds of miles away. It is hoped that people can learn to understand the vocalisations to help them predict their movements.

Blue whales existed incredibly low densities with enormous distances between them but, clearly, are sharing information in some way. – William Oestreich, a graduate student in biology at Stanford University’s Hopkins Marine Station, who led the study.

Whale vocalisations can barely be heard by people (the sounds “exist on the farthest reaches of human hearing”) and it was thought that the only vocalised during mating. This research has upended those beliefs. The study was published in the journal Current Biology.

Some more about the blue whale

They can reach a maximum length of 98 feet (29.9 m) with a weight of 173 tonnes (190 tons). It is the largest animal ever to have existed on the planet. There are five subspecies. Their diet is almost exclusively krill. Until 19th century they were abundant in all oceans. They were hunted to near extinction until the International Whaling Commission banned hunting of blue whales in 1967. It is estimated that 382,595 blue whales were caught and killed between 1868 and 1978.

Today, the population size is no more than 11% of what it was in 1911. It is believed that there are about 10,000 to 25,000. Their population is fragmented into quite small concentrations such as, for example, in the Eastern North Pacific it is believed that there are 1,647 while in the Northern Indian Ocean it is believed that there are 270. They are classified as endangered by the IUCN Red List.

Scientists can work out the age of blue whales through the air wax. It is deposited chronologically. The maximum age determine this way is 73 years. There is an exhibition of a blue whale skull which measures 19 feet in length.

It is believed that blue whale sometimes mate with fin whales to create a hybrid. One such hybrid was a 65 foot female which had features of both blue and fin whales living in the North Pacific. It is believed that the hearing range of whales is between 7 Hz to 22 kHz. Blue whale sounds are, as mentioned, the loudest and lowest in frequency made by any animal. Blue whales off Chile were estimated to make a sound as loud as 188 dB. The frequency range of blue whale soundss is between eight and 25 Hz. It is believed that they have between nine and 13 song types. The Wikipedia author says that the reason the vocalisations are uncertain but this research that I have mentioned on this page gives a clue as to the reasons for the sounds that they make. Other reasons might include, social organisation, location of prey sources and location of topographic features.