Two humpback whales set records swimming between Australia and Brazil
NEW YORK– Scientists have spotted two humpback whales that made separate, record-breaking crossings between Australia and Brazil.
The whales were identified by their distinctive tail markings at the two locations about 9,000 miles (14,500 kilometers) apart. They traveled in opposite directions and traveled farther than any humpback whale known so far.
“It’s a very rare event, but it’s a really wonderful demonstration of the breadth of the range of these animals,” said Phillip Clapham, former director of a NOAA whale research program, who was not involved in the new findings.
Humpback whales are known to travel long distances across major oceans in predictable patterns, usually following migration routes learned from their mothers. They feed on krill and small fish during the warmer months and breed in tropical waters during the winter.
It’s difficult to track the movements of creatures that spend most of their lives underwater. In the new study, scientists analyzed more than 19,000 images of whales taken over the past four decades by research groups and citizen scientists.
Recognition software helped identify the whales based on the colors and irregular edges of their tails. Researchers identified two different whales at breeding sites in eastern Australia and Brazil over the years, suggesting they had interbred between locations.
One whale traveled just over 9,300 miles (15,000 kilometers), surpassing previous record holders including a humpback whale that swam from Colombia to Zanzibar.
The results were published Tuesday in the journal Royal Society Open Science.
Because the photos only depict the whales at the beginning and end of their journey, researchers don’t know the exact route they took.
Whales don’t typically travel between mating sites, so it’s not yet clear why these two undertook their journeys separately. They may have encountered other whales at common feeding grounds and split up instead of returning where they came from, study co-author Stephanie Stack of the Pacific Whale Foundation said in an email.
“Finding not one but two individuals who crossed from Australia and Brazil challenges what we thought we knew about how separated these populations actually were,” Stack said.
Such odysseys are more difficult for whales in the Northern Hemisphere, where huge continents make ocean crossings more difficult.
Scientists said the record-breaking journey shows just how far humpback whales can go. These methods can also help track them as climate change warms the oceans, possibly altering where krill live and where humpback whales might go to feed and breed.
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