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.

Record numbers of marine mammals, like bottlenose dolphins, have been recorded in the United Kingdom.

UK sees record sightings of whales, dolphins and seals

The Wildlife Trusts, which comprises 46 individual wildlife trusts around the country, reports record numbers of more than 800 sightings of whales, dolphins and seals in the waters of the United Kingdom in 2019.

Its Yorkshire project reported hundreds of individual sightings by trained citizen scientists. Among these were a pod of bottlenose dolphins making their way from Scotland to Flamborough Head in East Yorkshire-the farthest south they had been officially identified.

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.

Wedell seal

Seals may use Earth's magnetic field to navigate

If the hypothesis turns out to be true, it would represent the first evidence of such a trait in a marine mammal.

Randall Davis of the Department of Marine Biology at Texas A&M University, Terrie Williams, a professor of ecology and evolutionary biology at the University of California, Santa Cruz and another colleague, Lee Fuiman, associate director of the University of Texas' Marine Science Institute in Port Aransas, have been studying the behaviour of Weddell's for decades.