Dolphins whistle to each other as part of a male bonding ritual and rely on ‘wingmen’ to vie for the affection of potential mates, new research has found.
Experts at the University of Bristol said bottlenose dolphins can become more popular simply through vocal exchanges, helping them to maintain weaker but vital social relationships.
Not only this, but a separate study found that the more popular a dolphin is with other males, the more successful it is when it comes to producing calves.
This research was carried out by the University of New South Wales and University of Western Australia.
It found that groups of male bottlenose dolphins will work together to compete with rival groups over access to females, with the most popular males in the group having the best mating success.
Dolphins whistle to each other as part of a male bonding ritual and rely on ‘wingmen’ to vie for the affection of potential mates, new research has found
The Bristol study found that male dolphins are able to stay popular by using high-pitched vocal exchanges (pictured) with other males as a low-cost way to maintain their alliances
The Bristol study, meanwhile, discovered that male dolphins are able to stay popular by using high-pitched vocal exchanges with other males as a low-cost way to maintain their alliances, rather than through other physical bonding activities.
Experts say this is an important interaction to maintain when groups become larger and competition over resources increases.
Lead author Emma Chereskin, a student at the University of Bristol, said: ‘Many animals, including humans, use tactile contact, touch, to strengthen and reaffirm important relationships.
‘But as the number of close social relationships increases, so too do the demands on the time and space available for relationship maintenance through physical contact.
‘Male bottlenose dolphins form strategic, multi-level alliances, and we wanted to know how they maintained multiple alliance relationships in large groups.’
While male dolphins are known to use physical contact such as gentle petting to connect with strongly bonded allies, the University of Bristol research shows they rely on less time-demanding vocal exchanges to remain connected with weaker allies.
Scientists used nine years of acoustic and behavioural data from a dolphin population in Shark Bay, Western Australia, which helped them assess how male dolphins bonded with each other.
Bottlenose dolphins team up to hunt or protect themselves from predators. Adult males live mostly alone or in groups of two to three and join pods for short periods of time.
These usually number around 10 to 30 members, although ‘superpods’ of more than 1,000 have been recorded.
Senior author Dr Stephanie King, also from Bristol, said: ‘We found within the core dolphin alliances, strongly bonded allies engaged in more affiliative contact behaviour, such as petting and rubbing, while weakly bonded allies engaged in more whistle exchanges.
‘This illustrates these weaker but still key social relationships can be maintained with vocal exchanges.’
Scientists used nine years of acoustic and behavioural data from a dolphin population in Shark Bay, Western Australia, which helped them assess how male dolphins bonded with each other
It backs British anthropologist Professor Robin Dunbar’s theory that vocalisations and language evolved to replace grooming.
Increasingly large group sizes placed impossible demands on the time available for physical contact.
Ms Chereskin said: ‘Our findings provide new evidence that vocal exchanges can serve a bonding function.
‘But more importantly and in line with the social bonding hypothesis, vocal exchanges can function as a replacement of physical bonding, allowing allied male dolphins to ‘bond-at-a-distance’.
‘This evidence in support of the social bonding hypothesis outside of the primate lineage raises exciting new questions on the origins and evolution of language across taxa.’
Bottlenose dolphins inhabit warm and temperate seas worldwide, being found everywhere except around the Arctic and Antarctic.
They are renowned for their intelligence, using marine sponges as tools to reach food that would normally be inaccessible, and communicate through pulsed sounds, clicks and body language.
The study has been published in the journal Current Biology.