Most of these sounds were measured at more than 21 kHz, which is beyond the range of human hearing of 20 to 20,000 hertz. A particular high-pitched whistle came in at 49.8 kHz. When the seals harmonised multiple tones, the resultant sound may exceed 200 kHz, which is beyond what even cats and dogs can hear).
The discovery was the subject of a paper published online in the journal The Journal of the Acoustical Society of America.
When whaling all but exterminated the Antarctic blue whale 50 years ago, the waters around South Georgia fell silent. Between 1998 and 2018, dedicated whale surveys off the sub-Antarctic island yielded a sole blue whale sighting. But a whale expedition this year and analysis by an international research team resulted in 58 blue whale sightings and numerous acoustic detections, raising hopes that the critically endangered mammal is finally recovering five decades after whaling was banned.
On our journey north of the polar circle, my fellow adventurers and I were greeted by an astonishing spectacle. Over 20 orca were hunting an animal so rare that few people have seen them in the wild, let alone had the chance to study them. Using immense strength, agility and cunning intelligence, the orca worked as a team to hold the Arnoux’s beaked whale under water to drown it.
South Georgia is the most well-known of the Falkland Islands, also called Islas Malvinas. It lies nearly at the end of the world in the Southern Atlantic Ocean. To find this place on the map, draw an equilateral triangle with one vertex on Cape Horn and another on the Antarctic Peninsula. The third vertex in the east is our destination.