In 2013, photographers recorded a humpback whale off the coast of Colombia. Nine years later, the same whale was photographed in a shockingly distant location.
An international team of researchers has identified one of the longest individual humpback whale migrations ever documented. This remarkable finding, detailed in a December 11 study published in the journal Royal Society Open Science, offers insight into the species’ complex behavior and the environmental factors that may trigger such long-distance journeys.
The researchers, including scientists from the Macuáticos Colombia Foundation, identified the humpback whale as an adult male. He was first photographed off the coast of Colombia on July 10, 2013. Almost a decade later, a researcher photographed the same whale in the Zanzibar channel between Tanzania and Zanzibar on August 22, 2022. The two sightings were at a great-circle distance of 8,106.4 miles apart (13,046 kilometers), likely representing the longest recorded distance a humpback whale has ever traveled, Ekaterina Kalashnikova of the Tanzania Cetaceans Program, who co-wrote the study, told the BBC.
A great-circle distance is the shortest distance between two points on a sphere, but “the exact migration route for this individual is unknown,” the researchers wrote in the study. In fact, it’s unlikely that the humpback whale swam as the crow flies, meaning that he probably traveled a much greater distance.
While humpback whales conduct some of the longest migrations of any animal in the world, this particular whale’s trip is nevertheless surprising. Humpback whales tend to follow the same longitudinal (north-south) migration patterns, usually visiting the same cold feeding grounds and warm breeding grounds, according to the study.
This whale, however, swapped breeding grounds and crossed three oceans latitudinally (east-west) to do it—also making him the first recorded humpback whale to change breeding grounds from the Pacific to the Indian Ocean. Another exception to the rule is a female humpback whale who previously traveled 6,125 miles (9,800 kilometres) from the Brazilian coast to Madagascar.
“The long-distance movement presented here appears to be atypical and raises the question as to what its drivers are, which could include but not necessarily be limited to mating strategies,” they wrote. In other words, the whale could have embarked on a trans-oceanic journey for sex.
“When he showed up, was it like, ‘Oooh, sexy foreigner with a cool accent’?” joked Ted Cheeseman of Southern Cross University, who co-wrote the study, as quoted by the Guardian.
“Other reasons behind this unusual new habitat exploration may be global climatic changes and altered environmental conditions and events,” the researchers wrote, adding that fluctuations in krill distribution in the Southern Ocean may be involved. They also speculated that an increase in the humpback whale population may be heightening competition for mates and resources, leading individuals to seek food and breeding grounds farther from their usual route.
The researchers acknowledged that “the exact cause or drivers of these breeding habitat shifts can only be speculated due to the current limited data availability on humpback whale behavioural ecology.” However, they added that the record migration highlights the species’ behavioral flexibility, which may aid humpback whales in adapting to environmental changes or could reflect evolutionary responses resulting in such pressures.
Researchers identified the humpback whale’s record-breaking journey thanks to photographs uploaded to the platform Happywhale, a website co-founded by Cheeseman where whale watchers can upload pictures of their whale sightings. The platform uses automated image recognition software to identify the whales in the images by the unique patterns on their flukes (their tails).
The study sheds light on the surprising behaviors of a complex marine animal, and may ultimately reveal insights about both humpback whales and their marine ecosystem.
Read the full article here
