1. Matching Tail Patterns to Track Humpback Whales from Costa Rica to Antarctica
The underside of a humpback whale’s tail has a unique black-and-white pattern, much like a human fingerprint. Scientists use photos of these patterns to identify individual whales. By matching photos taken in different locations, researchers found seven humpback whales that had been seen both off the Antarctic Peninsula and off Central America [1]. The minimum distance between the two sighting places was as much as 8,461 km (about 5,257 miles), which was the longest migration recorded for a mammal at that time [1].
Among these whales was the mother and calf pair mentioned earlier. They were seen off Costa Rica and then found off Antarctica 161 days later [1]. It is thought that the warm waters of Central America are used for birth and mating, while the cold waters of Antarctica are used for feeding. It is important to note the word "minimum." Photos only prove that the same whale was seen in two places. They do not show the exact path taken. The distance is a minimum between the two locations, not the length of the actual route. Also, the idea that this was the "longest migration" at the time may change as new research is done.
2. Why Do Humpback Whales Travel to Warm Seas? Four Theories
Humpback whales gather in warm seas to breed. A study of 24 breeding areas around the world found that water temperatures were between 21 and 28 degrees Celsius, with an average of 24.6 degrees Celsius [1]. But why do they choose warm water? There are several theories, and none is proven to be the only answer.
One theory suggests that low-latitude (warmer) seas have a lower risk of newborn calves being attacked by orcas (killer whales) [4]. Other theories suggest that warm, calm seas help calves maintain their body temperature, or that whales are following changes in food locations. Another idea is that this behavior is an old habit left over from evolution. However, there are arguments against the orca theory, so it is not certain.
In 2020, a new theory was proposed by Pitman and others. They suggested that whales might move to warm seas to keep their skin healthy. This idea came from tracking 62 orcas in Antarctica with satellite tags. Some of these orcas traveled about 11,000 km (about 6,835 miles) round trip to warm waters and back, resting little for 6 to 8 weeks [5]. This theory is mainly based on orcas. It is still being debated whether it applies directly to humpback whales. It is not yet a confirmed fact.
3. How Humpback Whales Keep a Straight Course in the Open Ocean
Researchers have put satellite tags on humpback whales to track them. In one study, whales kept a nearly straight course for several days. There were sections longer than 200 km (about 124 miles) where the whales stayed on course with high accuracy [2]. The ocean has currents, but the whales still maintained their direction.
However, scientists do not know how they do this. The study stated that known models for finding direction do not easily explain this behavior [2]. Also, humpback whales in the South Atlantic and South Pacific cross open oceans of more than 6,500 km (about 4,039 miles) at different times and along different routes. The authors said we need to look for "different compass mechanisms" [2]. Some researchers think whales might use the Earth’s magnetic field or the stars, but these are still just hypotheses.
4. Humpback Whale Migration Paths That Did Not Change in 15 Years
In 2020, Horton and others published a study comparing more than 15 years of satellite data for humpback whales on the South American side with old whaling records. They found that the corridor heading south-southeast, the straightness of the path, the direction, the timing, and the speed did not change much, even as the ocean and magnetic field changed [3].
The authors said that cues that keep changing, such as the magnetic field, may not be enough on their own to explain such steady routes, and they pointed to the possibility of more stable cues such as gravity. But this is only a possibility, not a proven mechanism [3]. We do not know if young whales learn the route from their mothers or if they are born with the ability.
5. Gray Whales: A Round-Trip Migration Along the Coast
Gray whales in the eastern North Pacific spend summers in the Bering and Chukchi seas, which are feeding grounds. In winter, they head to the coast of Baja California in Mexico. Calves are born in shallow bays either on the way south or between early January and mid-February [6].
The National Oceanic and Atmospheric Administration (NOAA) in the US says the round trip is about 10,000 miles (about 16,000 km), and sometimes more than 14,000 miles (about 22,530 km). Different sources give different numbers, ranging from 12,000 to 20,000 km (about 7,456 to 12,427 miles) [6].
In autumn, they swim south along the North American coast. From mid-February to May, they swim north along the same coast. This means people on the US West Coast can see them [6]. The route runs along the coast, but the source does not say whether the whales actually use coastal features to find their way.
6. Where Humpback Whales Travel Near Japan
Humpback whales in the North Pacific feed in high-latitude seas like the Aleutian Islands in summer. From winter to spring, they breed in subtropical and tropical seas around Ogasawara, Okinawa, Taiwan, and Hawaii. Their migration covers thousands of kilometers [7].
The Okinawa Churashima Foundation and others matched 3,532 tail photos taken in four areas: Okinawa, Ogasawara, Amami, and Hokkaido. In 2022, they announced that humpback whales coming to Japan are one common group, possibly with two smaller subgroups. There is some loyalty to each area [8].
In joint research with a group in the Philippines, tail patterns showed that some whales travel between Okinawa and the Philippines. 43.48% of whales seen in the Philippines were also seen in Okinawa, and some made the round trip in the same year [9].
7. Try It Yourself: Can You Keep a Direction Without Landmarks?
You can try a simple experiment at home to understand how hard it is to keep a direction without landmarks. Do this with an adult in a safe place, standing still.
Pick a distant landmark and face it. Close your eyes and point in that direction. Open your eyes and see how far off you were. Try this several times to see if you make the same mistake. This lets you see your own errors in direction. Human direction sense and whale course keeping are different questions, so they cannot be directly compared.
To learn more, you can read official information about humpback whales near Japan on the websites of the Okinawa Churashima Foundation or the Tokyo Islands Agriculture, Forestry and Fisheries Center [8][7]. Since we do not yet know exactly how whales find their way, think about what clues you would want to investigate if you were a scientist.