Despite being one of the biggest animals on Earth and occupying every ocean, the behavior of humpback whales has remained a mystery for scientists in many regards. Exactly where they mate in the Great Barrier Reef, how much they interact with each other and why they sing whale songs are some key cultural aspects of humpbacks that are still unknown. 

In 2022, photographers Lyle Krannichfeld and Brandi Romano were the first to observe and photograph two humpback whales mating. These photos, taken in the Pacific Ocean near Maui, Hawaii, have been released in a 2024  study by biologist Stephanie Stack. Humpback whales migrate farther than any marine mammal annually, often mating and giving birth in tropical waters such as the climate of Hawaii.

Romano and Krannichfeld sent their photographs to Stack, knowing that they had captured something incredibly important to the study of humpback whales. Stack was able to not only confirm that the whales were mating, but was also able to identify both whales as male. Though many theories have been produced about why the two males were mating, Stack told National Geographic that too little is known about humpback whale social dynamics to know what the motivation was behind their behavior. Following these photographs, humpback whales have joined the list of over 1,500 species where same-sex copulation has been observed.