Social lives of juvenile dolphins prepare them for adulthood

New research into the social lives of juvenile bottlenose dolphins has revealed choices involving friendships and activities can help prepare individuals for later life, especially with regards to their defined gender roles.

close contact
Researchers believe the friendships made by young dolphins and the activities they do together can help prepare them for later life

Bottlenose dolphins are often regarded as one of the most intelligent and social animals behind humans, with fantastic problem solving abilities, large groups and impressive communication skills. Until now not a lot has been known about how much early life shapes these complex creatures and prepares them for the rigorous societal demands put upon them in later life. However a new study, by researchers from Georgetown University and Duke University, has revealed that their early years play an important role in developing skills they will need in adulthood. In particular networking amongst peers and choices regarding activities, which differs significantly between genders to help prepare them for their very separate responsibilities in later life. These findings further reinforce just how remarkable these animals are, as well as how important social interactions are for the development of intelligent animals.

Early years

Like most cetaceans juvenile bottlenoses will spend the first few years of their lives alongside their mothers in small groups. At around 3 or 4 years old individuals will then leave the protection of their family groups and venture off on their own, living in ever-changing groups that come together, split up and come together again in different combinations. They will continue to do this until around 10 when they start to mature and assume more defined roles and groups. Little was previously known about how the juveniles behave during this period, especially in the absence of adults, and how important these years are to their development. It has long been suspected play is an important factor in developing social skills, with lots of documented examples, but until now a dedicated study into this stage of their lives had not been carried out.

group life
Juvenile dolphins spend their early years frequently switching between different groups

Studying social skills

To uncover more about this stage of the dolphins’ lives, researchers needed long-term datasets on juvenile bottlenoses. This was achieved by a team of researchers, from both Georgetown and Duke Universities, who analysed a near 30 year study on over 1700 bottlenose dolphins in Shark Bay in Western Australia. Looking at the observational data collected on individuals between the times they left their mothers and started to mature, they were able to focus on the behaviours, activities and social interactions of their most formative years. In doing so they uncovered lots of trends, especially between different genders, which they suspect prepare them for important roles in later life. The team revealed their results last month in their new paper published in the journal Behavioural Ecology.

juveniles playing
The researchers of the new study focused heavily on the relationships between individual juveniles and how they spent their time together

Boys & girls

The team found that juvenile dolphins would frequently change groups as often as every 10 minutes interacting with many different individuals a day, but only forming deep ‘friendships’ with a select few. The researchers believe this shows individuals have defined preferences on who they hang out with, the result usually being that close friends were the same gender. However between male and female bottlenose juveniles the amount of time they spend socializing with their peers is significantly different. Male dolphins spend a lot longer hanging out with other males and engage in more activities such as playing, rubbing flippers, mirroring movements and resting together. Whereas females spend less time interacting with other females and spend over double the amount of time practicing to hunt for food.

hunting
Whereas males spent more time socialising amongst their peers, females spent more time on their own learning skills like hunting

The researchers believe that the reason for these differences is that each gender is preparing for their very different roles in later life. When they reach maturity male dolphins will usually form groups of two to three in an attempt to get fertile females alone with them and coerce them to mate. By the time they grow up, males therefore need to have enough social savvy to build and maintain strong alliances, or lose out on their chance to get a girl. However females are the ones who will end up raising their shared offspring and therefore must be able to provide enough food for two, which is why they spend longer hunting. In a recent press release, lead author Allison Galezo explained that – “the juvenile period can be an opportunity to develop social skills that will be important in adulthood, without the high-stakes risks that go with sexual maturity”.


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