Seals & Sea lions

The hole in the ozone layer can cause eye damage in Antarctic animals.

Antarctic Wildlife Threatened by Lingering Hole in Ozone Layer

The ozone layer is back on our radar. Although its condition has improved after the Montreal Protocol was implemented, the hole reappears every spring over the Antarctic. 

In recent years, it is no longer just a winter phenomenon anymore; it Is stretching into the early summer, coinciding with crucial times in the life cycles of local wildlife and emerging vegetation, exposing them to the sun's ultraviolet rays. As our planet changes, the timing of this exposure could have profound effects on the delicate ecosystems of the Antarctic.

Male northern elephant seal
Male northern elephant seal

Elephant seals sleep and dive at the same time

A new study involving elephant seals fitted with caps similar to those worn by humans in sleep clinics to measure electroencephalographic activity, or brain waves, has revealed the seals take short naps during deep dives. Unlike other marine mammals, they enter rapid eye movement, or REM, sleep, with accompanying paralysis, but do so at depths below those occupied by their predators. 

The emergence of TB in Peru likely came from marine mammals such as seals and sea lions.
The emergence of TB in Peru likely came from marine mammals such as seals and sea lions.

Did marine mammals cause emergence of tuberculosis in the Americas?

DNA research has shown that Mycobacterium pinnipedii, which today causes tuberculosis (TB) primarily in pinnipeds, infected human populations living in the coastal areas of Peru prior to European colonisation

The earliest cases are found in Peru and northern Chile and are dated to ~700 CE, with possible cases occurring as early as 290 CE.

The researchers also discovered TB in the skeletons of people who lived nowhere near the coast some 400 to 1,000 years ago — a scenario incompatible with TB transmission directly from infected pinnipeds or their tissues.

How elephant seals know when to head home

Every year, many marine animals migrate between foraging areas and breeding sites, often managing their movements with precision.

For pregnant female elephant seals, they travel more than 10,000 kilometres across the Eastern North Pacific Ocean annually, before returning to their breeding beaches where they will give birth within five days of their arrival.

How do they achieve such precise timing, without any GPS or navigation software?

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.