Predator threat boosts friendships amongguppies2 February 2017

Guppies are known to develop long and stable socialrelationships. Credit: University of Exeter

Danger from predators causes animals to formstronger friendships, according to new research.

Scientists from the University of Exeter, Universityof York and University of the West Indies, StAugustine, observed Trinidadian guppies andfound the fish developed stronger and more stable social bonds when they thought predators were inthe area.

Intriguingly, this also coincided with social groupsbeing smaller - suggesting a possible conflictbetween being able to form strong socialrelationships and being able to live in larger socialgroups.

This is the first experimental evidence thatproximity to predators can increase the intensity ofanimal social relationships.

"This research is important in our efforts tounderstand why social bonds and friendshipsform," said first author Dr Robert Heathcote, of

Exeter's Centre for Research in Animal Behaviour.

"The effects of dangerous environments on socialbonds are also known in humans, such as betweensoldiers who form strong and long-lasting bondsduring active duty in war zones."

Previous research has shown guppies recogniseother individuals and develop long and stable socialrelationships.

In this study, fish were kept in pools and some wereexposed to model predators, while others were not.

In the experiment, guppies were kept in pools and somewere exposed to model predators. Credit: University ofExeter

Guppies frequently leave and join new shoals, andthe researchers measured social ties by seeinghow often the same fish swam together.

While all guppies developed stronger social bondswhen faced with predators, the effect was strongestamong those most at risk - the larger and bolderindividuals.

Many animal species gather in large social groupsto gain protection from predators, but the scientistsfound guppies formed smaller groups as they

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strengthened their social ties.

"We suggest this may reflect a conflict between thebenefits of forming larger groups and those offorming stronger relationships," said Dr SafiDarden, a co-author on the study.

"The maintenance of social relationships oftenrequires individual recognition, which can becognitively demanding when it involves largenumbers."

Professor Darren Croft, also a co-author on thestudy, said: "It is becoming increasingly clear thatsocial relationships, 'friendships', are widespreadacross vertebrate species.

"Just as in humans where our friendships canpredict our life expectancy, non-human animals canalso benefit from forming stable social bonds.

"Our new work suggests that living under the threatof predation may have played a key role in theevolution of social relationships, and more work isneeded to examine this across species."

The paper, entitled "Fear of predation drives stableand differentiated social relationships in guppies", ispublished in the journal Scientific Reports.

Provided by University of ExeterAPA citation: Predator threat boosts friendships among guppies (2017, February 2) retrieved 7 July 2018from https://phys.org/news/2017-02-predator-threat-boosts-friendships-guppies.html

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