Whales

Narwhal being tagged.
Narwhal being tagged.

Artificial intelligence shines light on narwhal's hunting behavior

Narwhals, notwithstanding their unicorn-like tusks, are a mysterious species. They live in distant Arctic regions and hunt as deep as 1,000 meters down. 

They orient themselves using echolocation, making clicking sounds to explore their surroundings. When they hunt, the clicking sounds turn into buzzing sounds as the interval times shorten.

The pygmy blue whale is the smallest subspecies of the blue whale (shown here).
The pygmy blue whale is the smallest subspecies of the blue whale (shown here).

Whale songs reveal new population of pygmy blue whales

A new population of pygmy blue whales has been discovered in the Indian Ocean, thanks to underwater nuclear bomb detectors that recorded their whale songs.

The research team, led by the University of New South Wales (UNSW), had been studying data from the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) which monitors international nuclear bomb testing, when an unusually strong signal caught their attention.

Mmo iwdg / Wikimedia Commons / CC BY-SA 3.0
Long-finned pilot whale cow with her calf, off the coast of Ireland. Photo by Mmo iwdg / Wikimedia Commons / CC BY-SA 3.0

Buoy in Celtic Sea tracks oceanic noise

Equipped with an autonomous hydrophone, the buoy's function is to conduct for the first time real-time acoustic monitoring of the water's cetaceans to assess how oceanic noise pollution affects them. 

Deployed as part of the Smart Whale Sounds project, it will also track the distribution and behaviour of whale species in real-time and be used to train machine learning models to identify different species' calls. 

Cetaceans have developed mechanisms against diseases such as cancer

Why whales don't seem to get cancer

Cetaceans were not limited by gravity in the buoyant marine environment and evolved multiple giant forms, exemplified today by the largest animal that has ever lived: the blue whale (Balaenoptera musculus).

There are tradeoffs, however, associated with large body size, including a higher lifetime risk of cancer due to a greater number of somatic cell divisions over time.  The largest whales can have ∼1,000 times more cells than a human, with long lifespans, leaving them theoretically susceptible to cancer. 

Narwhals in dense pack ice
Narwhals in dense pack ice

Narwhal's tusk tells on its feeding habits, and more

Using mercury and stable isotopes of carbon and nitrogen to obtain such information, the team were able to also analyse how the ice cover and the impact of potential toxic compounds have evolved over time.

Their findings were published in the Current Biology journal.

The tusks of the ten narwhals involved in the research were 150 to 248 cm long, and contained data from the time period 1962 to 2010.

The fin whale, also known as the finback whale, is the second-largest species on Earth after the blue whale.

Whales expand their distribution

Four of the six baleen whale species found in the western North Atlantic Ocean (humpback, sei, fin and blue) have changed their distribution patterns in the past decade.

Using 281 passive acoustic recorders moored to the sea floor from the Caribbean Sea to Greenland, researchers from the United States and Canada monitored the movements of the whales from 2004 to 2014. The findings of their study was published in the Global Change Biology journal.

Rice’s whales already considered endangered by the US with a population estimated at fewer than 100

Rice's whale confirmed as a new species

Rice's whale (Balaenoptera ricei), previously believed to be a population of Bryde’s whales, is an intermediate-sized species of baleen whale.

“I was surprised that there could be an unrecognized species of whale out there, especially in our backyard,”

—Lynsey Wilcox, geneticist with the US National Oceanic and Atmospheric Administration