Whales

Blue whale hybrids

Researchers analyzed the genomes of North Atlantic blue whales (Balaenoptera musculus musculus) and found surprisingly high levels of fin whale (Balaenoptera physalus) DNA, suggesting extensive interbreeding.

Blue whales, the largest animals on Earth, faced severe population decline due to historic whaling, leading to their current endangered status. The North Atlantic subspecies is particularly at risk. The study aimed to assess inbreeding within this population, crucial for their recovery.

A depiction shows Tutcetus rayanensis, belonging to the extinct group of early whales called basilosauridae, in its appearance around 41 million years ago within the Tethys Ocean.

Fossil triggers monumental change in our comprehension of whales' evolutionary history

With an estimated weight of 412.3 pounds (187 kilograms) and a length of 8.2 feet (2.5 meters), this newly documented species is roughly the size of a modern-day bottlenose dolphin.

Named Tutcetus rayanensis, this creature belonged to the extinct basilosauridae family, which was one of the earliest groups to become fully aquatic. As revealed in a study published in Communications Biology on Thursday, this diminutive specimen is considerably older than other basilosaurids from the Eocene Epoch.

Lithographic print of men in whaleboat lancing a sperm whale.

Iceland suspends controversial whale hunt

“I have taken the decision to suspend whaling” until 31 August, food minister Svandis Svavarsdottir said in a statement, after a recent government-commissioned report concluded the hunt does not comply with Iceland’s Animal Welfare Act.

The report which provided a video showing a whale being hunted for five hours concluded the killing of whales during the hunt took too long.

Animal rights groups and environmentalists hailed the decision, with the Humane Society International calling it “a major milestone in compassionate whale conservation”.

This blue whale was encountered near the Channel Islands of California.
This blue whale was encountered near the Channel Islands of California.

Sustainable shipping program protects endangered whales

Ship strikes are a major threat to whales globally and to the recovery of endangered blue, fin, and humpback whales in California waters. From 2007-2022, observed and documented deaths totalled 52 endangered whales, likely representing a small fraction of the annual total number of ship strikes.

Program

The voluntary incentive program ran from May 1, 2022 through December 15, 2022, with twenty-three shipping companies participating. The 10-knot target allowed ships to travel at an efficient operating load using less fuel and producing less pollution.

(stock photo) Not that close please. Drone flights should be kept above 30 m where they are unlikely to provoke disturbance among cetaceans.

Whales are bothered by drones getting too close

Drone footage of marine mammals helps us better understand their behaviour and social structure or simply provides us with some stunning footage we couldn't obtain otherwise. However, drones can also affect whales, dolphins and other mammals if flown too close.

So what is too close and what are safe distances?

Common Seal (Phoca vitulina vitulina)
The harbor (or harbour) seal (Phoca vitulina), also known as the common seal, is a true seal found along temperate and Arctic marine coastlines of the Northern Hemisphere

Bird flu is killing marine mammals

 

Last summer, the highly contagious strain of avian influenza, that was first detected in early winter 2021, had been spreading through North American birds made its way into marine mammals, causing a spike in seal strandings along the coast of Maine.

In June and July 2022, more than 150 dead or ailing seals washed ashore, a number that was approximately three times the normal rate for this time of the year. Of the 41 stranded seals tested for the virus, nearly half tested positive.

Whales have developed mechanisms against diseases such as cancer.
Whales have developed mechanisms against diseases such as cancer.

Why whales don't get cancer

Cancer should be a near certainty for whales, being the longest-living and largest mammals there are. Across species, the higher the number of cells, the greater the number of cell divisions and the higher the probability of DNA damage and the transformation of a normal cell into a cancerous one.

However, the occurrence of cancer does not show a correlation with body mass. The lack of correlation between body mass and cancer risk is known as Peto’s paradox.

Brains of stranded marine mammals have shown the hallmarks of Alzheimer’s disease, according to new research

Toothed whales show signs of Alzheimer's disease

A study of 22 toothed whales which died in strandings along the Scottish coast shows that some of them exhibited hallmarks of Alzheimer’s disease, and this might have—at least in part—caused the stranding incident.

The dolphin species involved in the study were five species: Risso’s dolphins, long-finned pilot whales, white-beaked dolphins, harbour porpoises and bottlenose dolphins.