In May 2026, a paper published in Royal Society Open Science documented the first direct evidence of bidirectional communication between two distant humpback whale populations. Based on a dataset comprising 19,283 photo IDs collected between 1984 and 2025, researchers confirmed that two individual humpback whales were observed both in the East Australian breeding population (E1) and the Brazilian breeding population (A)—two locations separated by over 14,000 kilometers in a straight line.
The intervals between these re-observations were 6 years and 22 years respectively, indicating that such transoceanic migrations are extremely rare and likely represent one-off events rather than shifts along regular migration routes. These findings support the ‘Southern Ocean Exchange Hypothesis,’ which posits that the Southern Ocean serves as a conduit for gene flow between humpback whale populations in different ocean basins. The researchers noted that recovery of whale populations alongside climate and environmental changes may have created conditions conducive to such ultra-long-distance migrations; global collaborative efforts involving whale photo-ID programs are crucial tools for identifying and quantifying such rare occurrences.