Researchers have identified two humpback whales that made separate, record-setting crossings between eastern Australia and Brazil. Scientists matched distinctive tail fluke patterns in photographs taken years apart, linking sightings at breeding sites roughly 14,500 kilometers apart.
The study drew on more than 19,000 images collected over the past four decades by research teams and citizen scientists. Automated recognition software helped pinpoint individual whales by the unique color patterns and jagged edges of their tails, allowing authors to confirm that the same animals appeared in both regions.
The two whales were found to have traveled in opposite directions, and at least one individual logged a journey just over 15,000 kilometers, surpassing previous humpback distance records, including a documented swim from Colombia to Zanzibar. The results were published in the journal Royal Society Open Science.
Former NOAA whale research program chief Phillip Clapham, who was not part of the study, called the findings a rare but striking demonstration of how far these animals can roam. Study co-author Stephanie Stack of the Pacific Whale Foundation noted that discovering two such cross-Atlantic travelers challenges assumptions about how separate humpback populations are.
Humpbacks typically follow long-distance migration routes learned from their mothers, feeding on krill and small fish during productive seasons and moving to tropical waters to breed. Because whales spend most of their lives underwater, tracking them is difficult; photographic archives and matching software are becoming vital tools for revealing unexpected movements.
Researchers do not know the exact routes these whales took, since the photos capture only endpoints. One possible explanation is that individuals met on shared feeding grounds and then split off instead of returning to their original mating areas. The team also noted that similar long ocean crossings are harder in the Northern Hemisphere, where large continents block straight routes.
Beyond expanding knowledge of humpback behavior, the study highlights a monitoring method that could be important as climate change alters ocean conditions and prey distributions, potentially shifting where humpbacks feed and breed in the future.
