Does wintering in Hawaii and spending the summer in Southeast Alaska sound good to you? That’s the schedule that Alaska’s humpback whales keep. It’s a three thousand mile journey one way. How do these long-distance travelers find their way?
I’m Lisa Strong for the Petersburg Marine Mammal Center.
Researchers in Alaska have identified more than a thousand individual whales by the unique markings on their tail flukes. Many of these whales return to the exact locations in Alaska year after year. The whales navigate across the vast open ocean, then negotiate their way through the convoluted waterways of the Inside Passage. They find a precise feeding spot, without the benefit of a map, chart, compass or GPS. Scientists still don’t know just how they do it, but they have theories.
Humpbacks may possess a sixth sense, one that detects variations in the Earth’s magnetic field from place to place. Scientists call it biomagnetic sense. We know that other animals, including Arctic terns, pigeons, and tuna use biomagnetic navigation. Biomagnetite is a material found in the brains of these other animals. It‘s also found in the brains of humpback whales, so it’s possible that humpbacks use biomagnetics as well. As humans we can easily see variations in the landscape, like hills, valleys, and mountains and remember these features when passing through again. Humpbacks may use biomagnetics in a similar way to visualize features in the underwater landscape.
Biomagnetics isn’t the only theory to explain how whales navigate to their favorite feeding areas in Alaska. Another suggests that whales may actually memorize the low frequency sounds projected off of underwater landmarks. Or each location may have unique sounds, smells or tastes that we don’t recognize.
However they do it, after going months without eating, that first gulp of fish or krill must be a welcome change.
