Every humpback whale has a tail fluke as distinct as a fingerprint, and for decades researchers and ordinary whale-watchers have been photographing them and uploading the images to a global platform called Happywhale. Nobody expected that pile of holiday snapshots and research photos to eventually prove something this dramatic: that individual whales are crossing entire oceans between breeding grounds thousands of kilometres apart, on opposite sides of the planet.
One humpback whale was tracked across 15,100 kilometres — the longest gap ever recorded between sightings of the same individual.
A team led by researchers at Griffith University ran an automated image-recognition algorithm over 19,283 high-quality fluke photographs collected between 1984 and 2025 from eastern Australia and Latin America, then had humans double-check every potential match by eye. Out of roughly 20,000 individual whales in the dataset, two matches stood out. One whale was photographed in Hervey Bay, Queensland in 2007 and again in 2013, then turned up off São Paulo, Brazil in 2019, a straight-line distance of about 14,200 kilometres, more than a third of the way around the planet. The other was first seen at Brazil's Abrolhos Bank nursery in 2003, in a group of nine adults, and then photographed alone in Hervey Bay in September 2025, twenty-two years later, a 15,100-kilometre gap that is now the longest distance ever documented between sightings of the same individual humpback whale.
Decades of Photos, One Discovery
Both whales were tracked between two completely separate breeding populations that scientists had assumed were largely isolated from each other, connected only by a shared feeding ground somewhere near Antarctica. Finding proof of direct, individual-level movement between them, in both directions, changes how researchers think about how humpback populations mix, share genes, and potentially spread song culture across ocean basins.
"These whales were photographed decades apart, by different people, in opposite parts of the world, separated by two different oceans, and yet we can connect their journey," said Griffith University PhD candidate Stephanie Stack, a co-author of the study. "Discoveries like this are only possible because of investment into long-term multi-decadal research programmes and international collaboration."
Image credit: Humpback whale breaching ocean surface