This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: The southern humpback whale migration is in full swing. Tens of thousands of whales are now making their journey from warm Australian waters in the north to their cold feeding grounds in Antarctica.
But snacking along the way provides much-needed replenishment. In a new study published in Marine Mammal Science, we investigated humpback whale feeding behavior on the east coast of Australia using information from citizen science and social media. We found that mid-latitude feeding is a common and widespread strategy among humpback whales.
This discovery challenges a long-held assumption about where and when whales feed. It could also help us better protect these magnificent animals. For many years, humpback whales have been described as "capital breeders." This theory suggests that the whales spend summer feeding on krill in Antarctica to build up fat reserves, then travel thousands of kilometers to low-latitude breeding grounds to mate and give birth.
Warm tropical waters are nutrient-poor, offering little opportunity to feed. Historically, whaling and stranding records also supported this "feast or famine" theory, with the vast majority of humpback whales caught during mid-latitude migration in Australian waters having empty stomachs. It was widely assumed that they relied solely on their fat stores to sustain their migration, mating and the intense energetic demands of nursing newborn calves.
Conducting long-term, large-scale systematic research surveys across thousands of kilometers of the Australian coastline isn't feasible because of the high cost involved. Instead, like other researchers turning to public photos and footage, we sourced information about feeding events from social media. We searched platforms such as Facebook and Instagram for public posts from whale-watching companies, drone pilots and dedicated whale enthusiasts.
Only posts featuring clear visual evidence of specific feeding behaviors were included. This included whales opening their mouths, lunging through the water column with expanded ventral pleats (the accordion-like grooves that cover a whale's underside), bubble-net feeding or surfacing directly through dense schools of baitfish. Our search resulted in 199 distinct feeding observations, representing an estimated 1,417 individual humpback whales documented feeding in Australian waters between 2013 and 2024.
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