Evidence is mounting rapidly for the social transmission of certain behaviours within some mammal populations. Dolphins are no exception and their ability to learn from others within their social groups may be an important factor when it comes to adapting to human induced change within their environments.
But what does ‘social transmission’ of behaviours actually mean? A great example is found in some of the bottlenose dolphins in Shark Bay, Western Australia that have learnt, through ‘social transmission’, to use sponges as tools to help extract prey. Calves learn this unique tool use behaviour from their mothers and dolphin researcher Janet Mann and her colleagues have also speculate that this behaviour seems to serves an affiliative function, where ‘spongers’ appear to be more ‘cliquish’ and prefer to associated with other ‘spongers’. This cliquish element might have an influence on how this type of novel behaviour spreads within a social group.
Until recently the focus of research on these sponging dolphins has been on the eastern gulf of Shark Bay. But new research on dolphins living in the western gulf identified 40 individual ‘spongers’. As with the eastern gulf dolphins, the majority of spongers were female, sponging in deep channel habitats. But in the eastern gulf there was no observed difference in the number of associates between spongers and non-spongers. Spongers in the eastern gulf foraged more often that deep-water non-spongers and group sizes in deep-water habitat were typically larger, perhaps as a result of differences in prey distribution, or perhaps these larger groups are related to higher predator abundance.
Detailed research such as this, which tracks individuals and their unique behaviours is helping scientist to shine a light on some of the complex and rich social lives of other species, such as these extraordinary tool using dolphins.