Pacific Whale Foundation researchers examining photos of humpback whale tails to identify individual whales — each whale's tail pattern is as unique as a human fingerprint.
Two humpback whales have surprised scientists by making record-breaking journeys between Australia and Brazil, traveling farther than any whale ever documented before.
Researchers spotted the whales at breeding sites on opposite sides of the globe — about 9,000 miles (14,500 kilometers) apart. One whale covered just over 9,300 miles (15,000 kilometers), beating the previous record of a humpback that had swam from Colombia to Zanzibar. The whales traveled in opposite directions, suggesting they each independently decided to cross the vast Pacific and Atlantic oceans.
Scientists identified the whales using their tails — each humpback's tail pattern is as unique as a human fingerprint. Researchers analyzed over 19,000 whale photos taken over the past 40 years by scientists and ordinary citizens who submitted their wildlife pictures. Recognition software helped match the whales' distinctive tail colors and jagged edges at both locations.
"It's a very rare event, but it is a really wonderful demonstration of just how wide-ranging these animals are," said Phillip Clapham, a whale researcher who previously led a NOAA research program and was not involved with the new study.
Humpback whales usually follow the same migration routes their mothers taught them — swimming to cold waters to eat tiny shrimp-like creatures called krill, then returning to warm tropical seas to breed. Scientists don't yet know why these two whales strayed from the pattern.
"Finding not one but two individuals that have crossed between Australia and Brazil challenges what we thought we knew about how separate these populations really are," said Stephanie Stack, a study co-author with the Pacific Whale Foundation. Stack suggested the whales may have met other whales at shared feeding grounds and simply chose a different direction when it was time to head back.
The findings were published in the journal Royal Society Open Science. Because researchers only have photos from the starting and ending points, they don't know exactly what route the whales took.
Scientists say this research helps them track whale populations as climate change warms the oceans. Warmer water may change where krill live, which could shift where whales travel to find food. Understanding how far these animals can roam gives researchers better tools to protect them.