Richards Collins: Bottlenose dolphins are social climbers

Research shows dolphins form 'old boy networks' like humans
Richards Collins: Bottlenose dolphins are social climbers

Of the 55 prime ministers who held office in Britain, 20 were educated at Eton College, seven attended Harrow School, and six went to Westminster School. 

These institutions offer both education and affiliation; having the ‘right’ friends is important in life. Nor are humans the only social-climbers. A paper just published claims that bottlenose dolphins also form ‘old boy networks’.

For the last 30 years, zoologists have studied dolphins in Shark Bay, Western Australia, logging the ages genders and behaviours of 1,700 individuals.

Recent research has focused on youngsters from birth to age 10, examining ‘how juvenile male and female bottlenose dolphins navigate this vulnerable period’. 

‘Grouping patterns’ and ‘social associations in the absence of adults’ have been identified.

Baby bottlenoses, the research shows, remain close to their mothers for the first three to four years of life. Then they begin making excursions on their own, approaching other dolphins. 

Engaging in group activities, they may swim closely together, rub flippers, and imitate each other’s behaviour. 

Youngsters move frequently from one group to the next, some remaining around for as little as 10 minutes before heading off to join another one. In due course, an individual starts spending more of its time with a few close associates.

Each sex, the scientists found, does its own thing; females prefer to be with females, males with males. Segregation is ‘driven by same-sex preference rather than opposite-sex avoidance’. Females tend to spend more time on their own. 

Males, being more gregarious, ‘cast a wider social net’. They form ‘strong same-sex associations’ and engage in more ‘affiliative behaviour’ than their sisters. Females engage in less social activity, spending more time hunting for food than do males.

Family and friends are important to dolphins, so networking during the childhood years is crucial. As adults, they will tend to live in ‘pods’, typically of about 15 members. These associations may endure for years, with younger members joining and leaving from time to time. 

Shoals of fish can be herded and targeted co-operatively. An individual might call on others for help when danger threatens. There are records of females being assisted during childbirth. A mother’s friends will babysit a calf, allowing her time off for fishing.

But dolphins also have a dark side. 

Just as a male lion, taking over a pod, kills the cubs of his predecessor so as to bring their mother into heat, a male dolphin will kill a youngster occasionally, so that he can impregnate its mother.

Fungie, the famous Dingle Bay resident, might appear to be a loner, but he’s not. He seems to have shunned others of his kind, in favour of human contacts.

As is the case with highly intelligent social animals generally, dolphins are slow to mature sexually; females don’t give birth to their first calf until age 10. 

The long childhood, the researchers suggest, allows the youngsters ‘to assess potential associates’ without the stress of having to compete for breeding partners while doing so.

How do bottlenoses recognise their friends? Do they use secret fin-shakes or are there dolphin equivalents of the Eton Boating Song in their extensive vocal repertoires?

Janet Mann et al. Juvenile social dynamics reflect adult reproductive strategies in bottlenose dolphins. Behavioural Ecology 2020

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