An adult male humpback whale swam a record migration of 8,106 miles between breeding grounds off Colombia and waters off Tanzania, according to a new study.
The study, published online Wednesday in the journal Royal Society Open Science, found that the whale made an unprecedented move from the eastern Pacific Ocean to the southwestern Indian Ocean, separated by at least 120 degrees of longitude.
It’s the longest recorded distance between two sightings of a single humpback at different wintering grounds.
It was spotted off Colombia in 2013 and 2017, then was observed off the coast of Tanzania in 2022. The mammal’s great trek is also the first known instance of a whale alternating between breeding grounds in the Pacific and Indian oceans.
While humpbacks are known for long migrations, these tend to occur by latitude between east and west rather than by longitude going north and south. Humpbacks are known to migrate more than 4,970 miles by latitude in a single direction, the study’s multinational team of researchers wrote.
As such, stocks of humpback whales tend to be distinct and stick to certain breeding grounds, with seven stocks observed in the Southern Hemisphere. This whale, however, went from the Pacific “stock G” to the Indian Ocean “stock C.”
Researchers weren’t certain what drove the male humpback to make such a long journey. It could have been to find mates or to find more krill, since populations of the thumb-sized crustaceans that the whales feed on fluctuate yearly, the authors said.
“An area that has previously been a good source of food for humpbacks might no longer sustain their needs, which will inevitably lead to them seeking out other areas to forage, which consequently can lead to an extension of their migratory track and possibly a different breeding ground after the feeding season,” study co-author Alex Vogel said in a release from the Bazaruto Center for Scientific Studies.