Along the turquoise waters of northern Australia, a group of dolphins decided to defy all natural conventions with a gesture as curious as it is fascinating: wearing sea sponges on their heads. This is not a simple game, but a real courtship ritual observed by researchers in the Dampier Archipelago, where the males of Sousa sahulensis – the so-called Australian suses – seem to show off these unusual accessories to attract the attention of females.
Scientists from the Department of Biodiversity, Conservation and Attractions (DBCA) documented several males swimming with sponges of different shapes, colors and sizes, carefully placed on their heads. Some wear them as wigs, others as ceremonial hats, but the meaning always seems the same: to show off. In some cases the dolphins even go so far as to offer the sponge to the chosen female, a gesture comparable to a symbolic gift, which seals a bond or an attempt at seduction.
This particular species was only officially recognized in 2014 and lives in tropical coastal areas between Australia and Southern New Guinea. With fewer than 10,000 estimated individuals, the Australian susa is classified as “vulnerable” on the IUCN red list, which makes any discovery about its behavior even more precious.
View this post on Instagram
A behavior already observed in killer whales
The fact that male dolphins wear sponges not out of necessity, but for social and symbolic reasons, represents a huge step forward in understanding animal culture. In fact, experts speak of learned, shared and handed down behavior, which arises from observation and imitation. In other words, these dolphins do not follow a genetic impulse, but consciously choose to express themselves through a gesture that communicates belonging and identity.
This brings them closer to other cetaceans known for their social creativity, such as orcas, observed wearing dead salmon as hats in a gesture of pure display. Ethologists interpret these phenomena as ways of communicating status or belonging, real cultural signs that cross generations.
View this post on Instagram
This isn’t the first time dolphins have found an ingenious use for sponges. In Shark Bay, further south, Indo-Pacific bottlenose dolphins (Tursiops aduncus) use these organisms not to seduce, but to hunt. They stick sponges on their rostrum – their elongated snout – to protect themselves from cuts and scrapes as they dig through rocks and corals in search of prey. This technique, called “sponging”, has been documented since the 1980s and is a clear example of tool use in marine mammals, passed down especially among females.
You might also be interested in:
