Seals & Sea lions

Researchers pick up nine new calls made by Weddell seals

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.

Palaeontologist and PhD student James Rule inspects the fossil skull of the newly identified monk seal species.
Palaeontologist and PhD student James Rule inspects the fossil skull of the newly identified monk seal species.

Discovery of seal fossils leads to new revelations

The discovery of the extinct monk seal species came about after an international team of biologists examined seven fossil specimens (including a complete skull) found on south Taranaki beaches in New Zealand between 2009 and 2016.

Named Eomonachus belegaerensis, the new species was about 2.5m long and weighed around 200 to 250kg. It is believed to have lived in the waters around New Zealand three million years ago.

Of seals and their whiskers

Some land animals like rats and shrews use their whiskers to explore, forage and move around. For the first time, a team of researchers, led by Robyn Grant of Manchester Metropolitan University, were able to show that pinnipeds too use their whiskers in a similar fashion.

The study, published in the Journal of Comparative Physiology A sought to measure and compare whisker movements and control amongst three pinniped species—California sea lions, harbor seals and Pacific walruses.

Rescuing Seals in Vladivostok

The larga is the spotted seal (Phoca largha) that lives in the North Pacific Ocean along the coasts of South Korea to Chukotka in Russia, and from Alaska to California in the United States. These seals choose coastal rocks in shallow bays for their rookeries. In winter time, larga seals spend a lot of time on ice near ice holes, or on floating ice floes along the coast. These seals feed on fishes, octopuses and shellfishes.

If seals quickly learn to associate pinging tags with food, so do other marine mammal species, including dolphins, fish-eating whales, and orcas.

Smart seals are using our pinging tags to find fish

The negative effects of anthropogenic noise on marine mammals can be pronounced, such as lethal whale strandings coinciding with exposure to military sonar. Acoustic deterrent devices (ADDs) aim to elicit avoidance responses in aquatic predators, such as seals, and are currently being used to reduce depredation in fisheries. However, seals that have previously found fish at a location close to an ADD quickly habituate to these sounds.