Seals & Sea lions

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.

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.

California Sea Lion (Zalophus californianus) seen in Santa Cruz, California

How seals avoid the bends

Documentation of lung collapse and estimation of the depth at which collapse occurs has been difficult and only obtained in a few species.

Researchers led by Birgitte McDonald at the Scripps Institution of Oceanography netted a female adult California sea lion (Zalophus californianus), anaesthetised the animal and fitted it with loggers to record oxygen pressure in its main artery and the time and depths to which it dived.