Happywhale tail-recognition software shows animal crossed oceans for an extraordinary migration
In a whale of a tale about whales’ tails, a team of marine ecologists has tracked a humpback whale (Megaptera novaeangliae) more than 13,000 kilometers, from Colombia to Tanzania. The observation was made possible by modified facial recognition software designed to identify the giant aquatic mammals by the distinctive shapes of their tales, or flukes. It beats the previous of record for a humpback of 10,000 kilometers.
Such a long migration “is extraordinary,” says Jeremy Goldbogen, a comparative physiologist at Stanford University who was not involved with the work, published recently in Royal Society Open Science. The observation also demonstrates the utility of the fluke-identification program, known as Happywhale.com, which examines photographs submitted by ordinary people as well as biologists, says Christie McMillan, a marine mammal biologist at the Fisheries and Oceans Canada Cetacean Research Program who was not involved with this work. Happywhale “is an incredibly valuable tool” that “has allowed for collaboration at a scale that could not have been possible before,” she says.
Not so long ago scientists would spend countless hours poring over photos of whale flukes, hoping to match images of the same individual by looking for unique color patterns, notches, scars, and other markings, McMillan recalls. However, 15 years ago, Ted Cheeseman, now a graduate student in marine ecology at Southern Cross University, reasoned there had to be a better way. For decades, he led nature tours off Antarctica and other polar regions, and he realized that when it came to tracking whales, people like his customers could provide a wealth of data. Thus, he launched Happywhale.
The program’s software instantly compares each fluke image submitted with more than 900,000 photographs from around the world. According to Cheeseman, who collaborates with many whale researchers, including Goldbogen and McMillan, these images cover 109,000 individuals, including one of “Old Timer,” who dates back to 1972 and was spotted again this summer.
It was Happywhale that identified the record-setting humpback. In 2013, and again in 2017, photos showed it hung around summer breeding grounds off Colombia, on the western coast of South America. Then in 2022, researchers caught sight of it in breeding grounds near Zanzibar, an archipelago of the eastern coast of Africa that’s part of Tanzania. The wanderer has a very distinctive fluke and so researchers could confidently match it up with the whale photographed a decade ago on the other side of the world in the eastern Pacific Ocean.
The find is surprising because humpbacks usually stick to the same ocean basin, and the Colombia population normally only migrates between its South American breeding grounds and feeding grounds off Antarctica.
“Humpback whales have complex behavior, but to find an adult male whale halfway around the world is unexpected,” Cheeseman says. Researchers sometimes find a whale that has shifted from one group to another found nearby, he notes. But to get to Tanzania, the wayward humpback would have passed through two groups in the Atlantic Ocean. “This is more ‘foreign’ than any humpback previously documented,” Cheeseman says.
The researchers don’t know where this whale went between these sightings. But it likely traveled to Antarctica before heading to the southwestern Indian Ocean, where another population breeds, says co-author Ekaterina Kalashnikova, a marine biologist at the Bazaruto Center for Scientific Studies who founded the Tanzania Cetaceans Program, which captured the earlier photos. So, it’s “very likely the distances [the animal swam] were even greater” than 13,000 kilometers, Kalashinikova says.
Scientists have no idea why this individual went wandering. “This could be a simple story of a deeply confused whale,” says Alexander Werth, a marine biologist at Hampden-Sydney College who was not involved with the work. “But it’s more likely that this intrepid explorer is a lonely male desperately seeking mates.”
The journey “can really help us understand the limits of what is possible for these animals,” adds Lisa Kettemer, a marine biologist with a focus on animal migration at the Arctic University of Norway who was not involved with the work. “The next challenge is to understand the drivers behind animal migrations like this.”
The observation also shows the potential of Happywhale to leverage citizen science to produce real discoveries, including in areas where whales are understudied, Kettemer says. “Citizen scientists can contribute immensely to our understanding of [these] migrations,” Kettemer says. (Science)
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