Whales

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. 

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.

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.

Belugas are gregarious, highly sociable and they regularly form small groups, or pods, which may contain between two and 25 individuals, with an average of 10 members.

Pods tend to be unstable, meaning individuals tend to move from pod to pod. Their behaviour, which includes sophisticated vocal repertoires, suggest that this marine mammal lives in complex societies. It has long been thought belugas formed social bonds around females that primarily comprise closely related individuals from the same maternal lineage, but this hypothesis has never been documented.

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

As at the end of January 2021, 68 north Atlantic right whales have been spotted in the waters off the coast of southeastern United States, a number that wildlife officials in Florida describe as “encouraging.”

Three of these are young calves that have been spotted for the first time.

The mothers of these calves are a 12-year-old whale named Champagne, a 19-year-old named Infinity and a 14-year-old with no recorded name (but is known simply as Catalog #3720).

There are different populations of blue whales worldwide, and each can be identified by its own whale songs.

A new population has been identified based on its unique whale song, recorded in three locations: the Arabian Sea coast of Oman, the Chagos Archipelago in the central Indian Ocean, and Madagascar in the southwest Indian Ocean.

This discovery was reported in the journal Endangered Species Research.

When whaling all but exterminated the Antarctic blue whale 50 years ago, the waters around South Georgia fell silent. Between 1998 and 2018, dedicated whale surveys off the sub-Antarctic island yielded a sole blue whale sighting. But a whale expedition this year and analysis by an international research team resulted in 58 blue whale sightings and numerous acoustic detections, raising hopes that the critically endangered mammal is finally recovering five decades after whaling was banned.